diff --git a/BUILD/SETUP.sh b/BUILD/SETUP.sh
index 150f9e28b41..779d0f1c660 100644
--- a/BUILD/SETUP.sh
+++ b/BUILD/SETUP.sh
@@ -39,8 +39,8 @@ global_warnings="-Wimplicit -Wreturn-type -Wswitch -Wtrigraphs -Wcomment -W -Wch
 c_warnings="$global_warnings -Wunused"
 cxx_warnings="$global_warnings -Woverloaded-virtual -Wsign-promo -Wreorder -Wctor-dtor-privacy -Wnon-virtual-dtor"
 
-alpha_cflags="-mcpu=ev6 -Wa,-mev6"	# Not used yet
-pentium_cflags="-mcpu=pentiumpro"
+#alpha_cflags="-mcpu=ev6 -Wa,-mev6"	# Not used yet
+#pentium_cflags="-mcpu=pentiumpro"
 sparc_cflags=""
 
 # be as fast as we can be without losing our ability to backtrace
diff --git a/configure.in b/configure.in
index a59f1e30ab2..10f8ca37a4b 100644
--- a/configure.in
+++ b/configure.in
@@ -388,15 +388,16 @@ AC_MSG_CHECKING("if we should use 'skip-locking' as default for $target_os")
 if expr "$target_os" : "[[Ll]]inux.*" > /dev/null
 then
   MYSQLD_DEFAULT_SWITCHES="--skip-locking"
-  IS_LINUX="true"
+  TARGET_LINUX="true"
   AC_MSG_RESULT("yes");
+  AC_DEFINE([TARGET_OS_LINUX], [1], [Whether we build for Linux])
 else
   MYSQLD_DEFAULT_SWITCHES=""
-  IS_LINUX="false"
+  TARGET_LINUX="false"
   AC_MSG_RESULT("no");
 fi
 AC_SUBST(MYSQLD_DEFAULT_SWITCHES)
-AC_SUBST(IS_LINUX)
+AC_SUBST(TARGET_LINUX)
 
 dnl Find paths to some shell programs
 AC_PATH_PROG(LN, ln, ln)
@@ -576,7 +577,7 @@ AC_SUBST(NOINST_LDFLAGS)
 # (this is true on the MySQL build machines to avoid NSS problems)
 #
 
-if test "$IS_LINUX" = "true" -a "$static_nss" = ""
+if test "$TARGET_LINUX" = "true" -a "$static_nss" = ""
 then
   tmp=`nm /usr/lib/libc.a  | grep _nss_files_getaliasent_r`
   if test -n "$tmp"
@@ -827,7 +828,7 @@ struct request_info *req;
 ])
 AC_SUBST(WRAPLIBS)
 
-if test "$IS_LINUX" = "true"; then
+if test "$TARGET_LINUX" = "true"; then
   AC_MSG_CHECKING([for atomic operations])
 
   AC_LANG_SAVE
@@ -870,7 +871,7 @@ int main()
     [ USE_PSTACK=no ])
   pstack_libs=
   pstack_dirs=
-  if test "$USE_PSTACK" = yes -a "$IS_LINUX" = "true" -a "$BASE_MACHINE_TYPE" = "i386" -a "$with_mit_threads" = "no"
+  if test "$USE_PSTACK" = yes -a "$TARGET_LINUX" = "true" -a "$BASE_MACHINE_TYPE" = "i386" -a "$with_mit_threads" = "no"
   then
     have_libiberty= have_libbfd=
     my_save_LIBS="$LIBS"
@@ -1239,63 +1240,98 @@ with_posix_threads="no"
 # Hack for DEC-UNIX (OSF1)
 if test "$with_named_thread" = "no" -a "$with_mit_threads" = "no"
 then
-  # Look for LinuxThreads.
-  AC_MSG_CHECKING("LinuxThreads")
-    grepres=`grep Linuxthreads /usr/include/pthread.h 2>/dev/null | wc -l`
-    getconfres=`which getconf >/dev/null && getconf GNU_LIBPTHREAD_VERSION | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ |grep LINUXTHREADS | wc -l || echo 0`
-    if test "$grepres" -gt 0 -o "$getconfres" -gt 0
+    AC_MSG_CHECKING("Linux threads")
+    if test "$TARGET_LINUX" = "true"
     then
-      AC_MSG_RESULT("Found")
-      AC_DEFINE(HAVE_LINUXTHREADS)
-      # Linux 2.0 sanity check
-      AC_TRY_COMPILE([#include <sched.h>], [int a = sched_get_priority_min(1);], ,
-      AC_MSG_ERROR([Syntax error in sched.h. Change _P to __P in the /usr/include/sched.h file. See the Installation chapter in the Reference Manual]))
-      # RedHat 5.0 does not work with dynamic linking of this. -static also
-      # gives a speed increase in linux so it does not hurt on other systems.
-      with_named_thread="-lpthread"
-    else
-      AC_MSG_RESULT("Not found")
-      # If this is a linux machine we should barf
-      AC_MSG_CHECKING("NPTL")
-      if test "$IS_LINUX" = "true"
-      then
-        getconfres=`which getconf >/dev/null && getconf GNU_LIBPTHREAD_VERSION | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ |grep NPTL | wc -l || echo 0`
-        if test "$getconfres" -gt 0
+        AC_MSG_RESULT("starting")
+        # use getconf to check glibc contents
+        AC_MSG_CHECKING("getconf GNU_LIBPTHREAD_VERSION")
+        case `getconf GNU_LIBPTHREAD_VERSION | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ` in
+        NPTL* )
+                AC_MSG_RESULT("NPTL")
+                AC_DEFINE([HAVE_NPTL], [1], [NPTL threads implementation])
+                with_named_thread="-lpthread"
+                ;;
+        LINUXTHREADS* )
+                AC_MSG_RESULT("Linuxthreads")
+                AC_DEFINE([HAVE_LINUXTHREADS], [1],
+                      [Whether we are using Xavier Leroy's LinuxThreads])
+                with_named_thread="-lpthread"
+                ;;
+        * )
+                AC_MSG_RESULT("unknown")
+                ;;
+        esac
+        if test "$with_named_thread" = "no"
         then
-          AC_DEFINE(HAVE_LINUXTHREADS) dnl All this code predates NPTL, so "have linuxthreads" is a poor name.
-          with_named_thread="-lpthread"
-        else
-          AC_MSG_ERROR([This is a Linux system and neither Linuxthreads nor NPTL were
-found. Please install Linuxthreads or a new glibc and try 
-again.  See the Installation chapter in the Reference Manual for 
-more information.])
-        fi
-      else
-	AC_MSG_CHECKING("DEC threads")
-        if test -f /usr/shlib/libpthread.so -a -f /usr/lib/libmach.a -a -f /usr/ccs/lib/cmplrs/cc/libexc.a
-	then
-	  with_named_thread="-lpthread -lmach -lexc"
-	  CFLAGS="$CFLAGS -D_REENTRANT"
-	  CXXFLAGS="$CXXFLAGS -D_REENTRANT"
-	  AC_DEFINE(HAVE_DEC_THREADS)
-	  AC_MSG_RESULT("yes")
-	else
-	  AC_MSG_RESULT("no")
-	  AC_MSG_CHECKING("DEC 3.2 threads")
-          if test -f /usr/shlib/libpthreads.so -a -f /usr/lib/libmach.a -a -f /usr/ccs/lib/cmplrs/cc/libexc.a
-	  then
-	    with_named_thread="-lpthreads -lmach -lc_r"
-	    AC_DEFINE(HAVE_DEC_THREADS)
-	    AC_DEFINE(HAVE_DEC_3_2_THREADS)
-            with_osf32_threads="yes"
-            MYSQLD_DEFAULT_SWITCHES="--skip-thread-priority"
-	    AC_MSG_RESULT("yes")
-	  else
-	    AC_MSG_RESULT("no")
+          # old method, check headers
+          # Look for LinuxThreads.
+          AC_MSG_CHECKING("LinuxThreads in header file comment")
+          res=`grep Linuxthreads /usr/include/pthread.h 2>/dev/null | wc -l`
+          if test "$res" -gt 0
+          then
+            AC_MSG_RESULT("Found")
+            AC_DEFINE([HAVE_LINUXTHREADS], [1],
+                  [Whether we are using Xavier Leroy's LinuxThreads])
+            # Linux 2.0 sanity check
+            AC_TRY_COMPILE([#include <sched.h>], [int a = sched_get_priority_min(1);], ,
+            AC_MSG_ERROR([Syntax error in sched.h. Change _P to __P in the /usr/include/sched.h file. See the Installation chapter in the Reference Manual]))
+            # RedHat 5.0 does not work with dynamic linking of this. -static also
+            # gives a speed increase in linux so it does not hurt on other systems.
+            with_named_thread="-lpthread"
+          else
+            AC_MSG_RESULT("Not found")
+            # If this is a linux machine we should barf
+            AC_MSG_ERROR([This is a Linux system without a working getconf,
+and Linuxthreads was not found. Please install it (or a new glibc) and try again.
+See the Installation chapter in the Reference Manual for more information.])
           fi
-	fi
-     fi
-   fi
+        else
+          AC_MSG_RESULT("no need to check headers")
+        fi
+        AC_MSG_CHECKING("for pthread_create in -lpthread");
+        ac_save_LIBS="$LIBS"
+        LIBS="$LIBS -lpthread"
+        AC_TRY_LINK( [#include <pthread.h>],
+              [ (void) pthread_create((pthread_t*) 0,(pthread_attr_t*) 0, 0, 0); ],
+              AC_MSG_RESULT("yes"),
+              [ AC_MSG_RESULT("no")
+                AC_MSG_ERROR([
+This is a Linux system claiming to support threads, either Linuxthreads or NPTL, but linking a test program failed.
+Please install one of these (or a new glibc) and try again.
+See the Installation chapter in the Reference Manual for more information.]) ]
+              )
+        LIBS="$ac_save_LIBS"
+    else
+        AC_MSG_RESULT("no")
+    fi  # "$TARGET_LINUX"
+fi  # "$with_named_thread" = "no" -a "$with_mit_threads" = "no"
+
+if test "$with_named_thread" = "no" -a "$with_mit_threads" = "no"
+then
+  AC_MSG_CHECKING("DEC threads")
+  if test -f /usr/shlib/libpthread.so -a -f /usr/lib/libmach.a -a -f /usr/ccs/lib/cmplrs/cc/libexc.a
+  then
+    with_named_thread="-lpthread -lmach -lexc"
+    CFLAGS="$CFLAGS -D_REENTRANT"
+    CXXFLAGS="$CXXFLAGS -D_REENTRANT"
+    AC_DEFINE(HAVE_DEC_THREADS)
+    AC_MSG_RESULT("yes")
+  else
+    AC_MSG_RESULT("no")
+    AC_MSG_CHECKING("DEC 3.2 threads")
+    if test -f /usr/shlib/libpthreads.so -a -f /usr/lib/libmach.a -a -f /usr/ccs/lib/cmplrs/cc/libexc.a
+    then
+      with_named_thread="-lpthreads -lmach -lc_r"
+      AC_DEFINE(HAVE_DEC_THREADS)
+      AC_DEFINE(HAVE_DEC_3_2_THREADS)
+      with_osf32_threads="yes"
+      MYSQLD_DEFAULT_SWITCHES="--skip-thread-priority"
+      AC_MSG_RESULT("yes")
+    else
+      AC_MSG_RESULT("no")
+    fi
+  fi
 fi
 
 
@@ -1720,7 +1756,7 @@ fi
 AC_SUBST(COMPILATION_COMMENT)
 
 AC_MSG_CHECKING("need of special linking flags")
-if test "$IS_LINUX" = "true" -a "$ac_cv_prog_gcc" = "yes" -a "$all_is_static" != "yes"
+if test "$TARGET_LINUX" = "true" -a "$ac_cv_prog_gcc" = "yes" -a "$all_is_static" != "yes"
 then
   LDFLAGS="$LDFLAGS -rdynamic"
   AC_MSG_RESULT("-rdynamic")
@@ -1873,6 +1909,7 @@ AC_CHECK_FUNCS(alarm bmove \
  tell atod memcpy memmove \
  setupterm strcasecmp sighold vidattr lrand48 localtime_r \
  sigset sigthreadmask pthread_sigmask pthread_setprio pthread_setprio_np \
+ sigaction sigemptyset sigaddset \
  pthread_setschedparam pthread_attr_setprio pthread_attr_setschedparam \
  pthread_attr_create pthread_getsequence_np pthread_attr_setstacksize \
  pthread_attr_getstacksize pthread_key_delete \
@@ -1884,7 +1921,7 @@ CFLAGS="$ORG_CFLAGS"
 # Sanity check: We chould not have any fseeko symbol unless
 # large_file_support=yes
 AC_CHECK_FUNCS(fseeko,
-[if test "$large_file_support" = no -a "$IS_LINUX" = "true";
+[if test "$large_file_support" = no -a "$TARGET_LINUX" = "true";
 then
   AC_MSG_ERROR("Found fseeko symbol but large_file_support is not enabled!");
 fi]
diff --git a/include/my_global.h b/include/my_global.h
index 37e53c65dec..f0e600e386d 100644
--- a/include/my_global.h
+++ b/include/my_global.h
@@ -97,7 +97,7 @@
 
 
 /* Fix problem with S_ISLNK() on Linux */
-#if defined(HAVE_LINUXTHREADS)
+#if defined(TARGET_OS_LINUX) || defined(__GLIBC__)
 #undef  _GNU_SOURCE
 #define _GNU_SOURCE 1
 #endif
diff --git a/include/my_pthread.h b/include/my_pthread.h
index 7620b46e08b..a336d4dc288 100644
--- a/include/my_pthread.h
+++ b/include/my_pthread.h
@@ -286,8 +286,8 @@ extern int my_pthread_create_detached;
 #undef HAVE_PTHREAD_RWLOCK_RDLOCK
 #undef HAVE_SNPRINTF
 
-#define sigset(A,B) pthread_signal((A),(void (*)(int)) (B))
-#define signal(A,B) pthread_signal((A),(void (*)(int)) (B))
+#define my_sigset(A,B) pthread_signal((A),(void (*)(int)) (B))
+#define my_signal(A,B) pthread_signal((A),(void (*)(int)) (B))
 #define my_pthread_attr_setprio(A,B)
 #endif /* defined(PTHREAD_SCOPE_GLOBAL) && !defined(PTHREAD_SCOPE_SYSTEM) */
 
@@ -324,14 +324,27 @@ extern int my_pthread_cond_init(pthread_cond_t *mp,
 #if !defined(HAVE_SIGWAIT) && !defined(HAVE_mit_thread) && !defined(HAVE_rts_threads) && !defined(sigwait) && !defined(alpha_linux_port) && !defined(HAVE_NONPOSIX_SIGWAIT) && !defined(HAVE_DEC_3_2_THREADS) && !defined(_AIX)
 int sigwait(sigset_t *setp, int *sigp);		/* Use our implemention */
 #endif
-#if !defined(HAVE_SIGSET) && !defined(HAVE_mit_thread) && !defined(sigset)
-#define sigset(A,B) do { struct sigaction s; sigset_t set;              \
-                         sigemptyset(&set);                             \
-                         s.sa_handler = (B);                            \
-                         s.sa_mask    = set;                            \
-                         s.sa_flags   = 0;                              \
-                         sigaction((A), &s, (struct sigaction *) NULL); \
+
+/*
+  We define my_sigset() and use that instead of the system sigset() so that
+  we can favor an implementation based on sigaction(). On some systems, such
+  as Mac OS X, sigset() results in flags such as SA_RESTART being set, and
+  we want to make sure that no such flags are set.
+*/
+#if defined(HAVE_SIGACTION) && !defined(my_sigset)
+#define my_sigset(A,B) do { struct sigaction s; sigset_t set; int rc;      \
+                            DBUG_ASSERT((A) != 0);                         \
+                            sigemptyset(&set);                             \
+                            s.sa_handler = (B);                            \
+                            s.sa_mask    = set;                            \
+                            s.sa_flags   = 0;                              \
+                            rc= sigaction((A), &s, (struct sigaction *) NULL); \
+                            DBUG_ASSERT(rc == 0);                          \
                        } while (0)
+#elif defined(HAVE_SIGSET) && !defined(my_sigset)
+#define my_sigset(A,B) sigset((A),(B))
+#elif !defined(my_sigset)
+#define my_sigset(A,B) signal((A),(B))
 #endif
 
 #ifndef my_pthread_setprio
@@ -416,7 +429,7 @@ struct tm *localtime_r(const time_t *clock, struct tm *res);
 #undef	pthread_detach_this_thread
 #define pthread_detach_this_thread() { pthread_t tmp=pthread_self() ; pthread_detach(tmp); }
 #undef sigset
-#define sigset(A,B) pthread_signal((A),(void (*)(int)) (B))
+#define my_sigset(A,B) pthread_signal((A),(void (*)(int)) (B))
 #endif
 
 #if ((defined(HAVE_PTHREAD_ATTR_CREATE) && !defined(HAVE_SIGWAIT)) || defined(HAVE_DEC_3_2_THREADS)) && !defined(HAVE_CTHREADS_WRAPPER)
@@ -663,6 +676,15 @@ extern struct st_my_thread_var *_my_thread_var(void) __attribute__ ((const));
 */
 extern pthread_t shutdown_th, main_th, signal_th;
 
+/* Which kind of thread library is in use */
+
+#define THD_LIB_OTHER 1
+#define THD_LIB_NPTL  2
+#define THD_LIB_LT    4
+
+extern uint thd_lib_detected;
+extern uint thr_client_alarm;
+
 	/* statistics_xxx functions are for not essential statistic */
 
 #ifndef thread_safe_increment
diff --git a/include/thr_alarm.h b/include/thr_alarm.h
index 7a10d6886ce..ef6aaf49f77 100644
--- a/include/thr_alarm.h
+++ b/include/thr_alarm.h
@@ -25,11 +25,6 @@ extern "C" {
 #ifndef USE_ALARM_THREAD
 #define USE_ONE_SIGNAL_HAND		/* One must call process_alarm */
 #endif
-#ifdef HAVE_LINUXTHREADS
-#define THR_CLIENT_ALARM SIGALRM
-#else
-#define THR_CLIENT_ALARM SIGUSR1
-#endif
 #ifdef HAVE_rts_threads
 #undef USE_ONE_SIGNAL_HAND
 #define USE_ALARM_THREAD
@@ -98,6 +93,8 @@ typedef struct st_alarm {
   my_bool malloced;
 } ALARM;
 
+extern uint thr_client_alarm;
+
 #define thr_alarm_init(A) (*(A))=0
 #define thr_alarm_in_use(A) (*(A)!= 0)
 void init_thr_alarm(uint max_alarm);
diff --git a/mysys/default.c b/mysys/default.c
index 25e283a9650..911f516dad8 100644
--- a/mysys/default.c
+++ b/mysys/default.c
@@ -282,7 +282,7 @@ static int search_default_file(DYNAMIC_ARRAY *args, MEM_ROOT *alloc,
 {
   char **ext;
 
-  for (ext= (char**) f_extensions; *ext; *ext++)
+  for (ext= (char**) f_extensions; *ext; ext++)
   {
     int error;
     if ((error= search_default_file_with_ext(args, alloc, dir, *ext,
@@ -543,7 +543,7 @@ void print_defaults(const char *conf_file, const char **groups)
 #endif
     for (dirs=default_directories ; *dirs; dirs++)
     {
-      for (ext= (char**) f_extensions; *ext; *ext++)
+      for (ext= (char**) f_extensions; *ext; ext++)
       {
 	const char *pos;
 	char *end;
diff --git a/mysys/my_pthread.c b/mysys/my_pthread.c
index a8157cc2f91..fd716448e43 100644
--- a/mysys/my_pthread.c
+++ b/mysys/my_pthread.c
@@ -31,6 +31,9 @@
 #define SCHED_POLICY SCHED_OTHER
 #endif
 
+uint thd_lib_detected;
+uint thr_client_alarm;
+
 #ifndef my_pthread_setprio
 void my_pthread_setprio(pthread_t thread_id,int prior)
 {
@@ -320,7 +323,9 @@ void *sigwait_thread(void *set_arg)
       sigaction(i, &sact, (struct sigaction*) 0);
     }
   }
-  sigaddset(set,THR_CLIENT_ALARM);
+  /* Ensure that init_thr_alarm() is called */
+  DBUG_ASSERT(thr_client_alarm);
+  sigaddset(set, thr_client_alarm);
   pthread_sigmask(SIG_UNBLOCK,(sigset_t*) set,(sigset_t*) 0);
   alarm_thread=pthread_self();			/* For thr_alarm */
 
diff --git a/mysys/my_thr_init.c b/mysys/my_thr_init.c
index 878a861bc94..5729f27b7a7 100644
--- a/mysys/my_thr_init.c
+++ b/mysys/my_thr_init.c
@@ -21,6 +21,7 @@
 
 #include "mysys_priv.h"
 #include <m_string.h>
+#include <signal.h>
 
 #ifdef THREAD
 #ifdef USE_TLS
@@ -44,6 +45,8 @@ pthread_mutexattr_t my_fast_mutexattr;
 pthread_mutexattr_t my_errchk_mutexattr;
 #endif
 
+static uint get_thread_lib(void);
+
 /*
   initialize thread environment
 
@@ -57,6 +60,12 @@ pthread_mutexattr_t my_errchk_mutexattr;
 
 my_bool my_thread_global_init(void)
 {
+  thd_lib_detected= get_thread_lib();
+  if (thd_lib_detected == THD_LIB_LT)
+    thr_client_alarm= SIGALRM;
+  else
+    thr_client_alarm= SIGUSR1;
+
   if (pthread_key_create(&THR_KEY_mysys,0))
   {
     fprintf(stderr,"Can't initialize threads: error %d\n",errno);
@@ -276,4 +285,20 @@ const char *my_thread_name(void)
 }
 #endif /* DBUG_OFF */
 
+
+static uint get_thread_lib(void)
+{
+  char buff[64];
+    
+#ifdef _CS_GNU_LIBPTHREAD_VERSION
+  confstr(_CS_GNU_LIBPTHREAD_VERSION, buff, sizeof(buff));
+
+  if (!strncasecmp(buff, "NPTL", 4))
+    return THD_LIB_NPTL;
+  if (!strncasecmp(buff, "linuxthreads", 12))
+    return THD_LIB_LT;
+#endif
+  return THD_LIB_OTHER;
+}
+
 #endif /* THREAD */
diff --git a/mysys/thr_alarm.c b/mysys/thr_alarm.c
index 54aa4d421f6..8f342e269de 100644
--- a/mysys/thr_alarm.c
+++ b/mysys/thr_alarm.c
@@ -37,6 +37,7 @@
 #define ETIME ETIMEDOUT
 #endif
 
+uint thr_client_alarm;
 static int alarm_aborted=1;			/* No alarm thread */
 my_bool thr_alarm_inited= 0;
 volatile my_bool alarm_thread_running= 0;
@@ -59,9 +60,7 @@ static void *alarm_handler(void *arg);
 #define reschedule_alarms() pthread_kill(alarm_thread,THR_SERVER_ALARM)
 #endif
 
-#if THR_CLIENT_ALARM != SIGALRM || defined(USE_ALARM_THREAD)
 static sig_handler thread_alarm(int sig __attribute__((unused)));
-#endif
 
 static int compare_ulong(void *not_used __attribute__((unused)),
 			 byte *a_ptr,byte* b_ptr)
@@ -77,21 +76,19 @@ void init_thr_alarm(uint max_alarms)
   alarm_aborted=0;
   init_queue(&alarm_queue,max_alarms+1,offsetof(ALARM,expire_time),0,
 	     compare_ulong,NullS);
-  sigfillset(&full_signal_set);			/* Neaded to block signals */
+  sigfillset(&full_signal_set);			/* Needed to block signals */
   pthread_mutex_init(&LOCK_alarm,MY_MUTEX_INIT_FAST);
   pthread_cond_init(&COND_alarm,NULL);
-#if THR_CLIENT_ALARM != SIGALRM || defined(USE_ALARM_THREAD)
-#if defined(HAVE_mit_thread)
-  sigset(THR_CLIENT_ALARM,thread_alarm);	/* int. thread system calls */
-#else
+  if (thd_lib_detected == THD_LIB_LT)
+    thr_client_alarm= SIGALRM;
+  else
+    thr_client_alarm= SIGUSR1;
+#ifndef USE_ALARM_THREAD
+  if (thd_lib_detected != THD_LIB_LT)
+#endif
   {
-    struct sigaction sact;
-    sact.sa_flags = 0;
-    sact.sa_handler = thread_alarm;
-    sigaction(THR_CLIENT_ALARM, &sact, (struct sigaction*) 0);
+    my_sigset(thr_client_alarm, thread_alarm);
   }
-#endif
-#endif
   sigemptyset(&s);
   sigaddset(&s, THR_SERVER_ALARM);
   alarm_thread=pthread_self();
@@ -109,13 +106,14 @@ void init_thr_alarm(uint max_alarms)
   }
 #elif defined(USE_ONE_SIGNAL_HAND)
   pthread_sigmask(SIG_BLOCK, &s, NULL);		/* used with sigwait() */
-#if THR_SERVER_ALARM == THR_CLIENT_ALARM
-  sigset(THR_CLIENT_ALARM,process_alarm);	/* Linuxthreads */
-  pthread_sigmask(SIG_UNBLOCK, &s, NULL);
-#endif
+  if (thd_lib_detected == THD_LIB_LT)
+  {
+    my_sigset(thr_client_alarm, process_alarm);        /* Linuxthreads */
+    pthread_sigmask(SIG_UNBLOCK, &s, NULL);
+  }
 #else
+  my_sigset(THR_SERVER_ALARM, process_alarm);
   pthread_sigmask(SIG_UNBLOCK, &s, NULL);
-  sigset(THR_SERVER_ALARM,process_alarm);
 #endif
   DBUG_VOID_RETURN;
 }
@@ -163,7 +161,7 @@ my_bool thr_alarm(thr_alarm_t *alrm, uint sec, ALARM *alarm_data)
 
   now=(ulong) time((time_t*) 0);
   pthread_sigmask(SIG_BLOCK,&full_signal_set,&old_mask);
-  pthread_mutex_lock(&LOCK_alarm);	/* Lock from threads & alarms */
+  pthread_mutex_lock(&LOCK_alarm);        /* Lock from threads & alarms */
   if (alarm_aborted > 0)
   {					/* No signal thread */
     DBUG_PRINT("info", ("alarm aborted"));
@@ -249,7 +247,7 @@ void thr_end_alarm(thr_alarm_t *alarmed)
       if (alarm_data->malloced)
 	my_free((gptr) alarm_data,MYF(0));
       found++;
-#ifndef DBUG_OFF
+#ifdef DBUG_OFF
       break;
 #endif
     }
@@ -258,10 +256,11 @@ void thr_end_alarm(thr_alarm_t *alarmed)
   if (!found)
   {
     if (*alarmed)
-      fprintf(stderr,"Warning: Didn't find alarm %lx in queue of %d alarms\n",
-	      (long) *alarmed, alarm_queue.elements);
-    DBUG_PRINT("warning",("Didn't find alarm %lx in queue\n",
-			  (long) *alarmed));
+      fprintf(stderr,
+              "Warning: Didn't find alarm 0x%lx in queue of %d alarms\n",
+              (long) *alarmed, alarm_queue.elements);
+    DBUG_PRINT("warning",("Didn't find alarm 0x%lx in queue\n",
+                         (long) *alarmed));
   }
   pthread_mutex_unlock(&LOCK_alarm);
   pthread_sigmask(SIG_SETMASK,&old_mask,NULL);
@@ -283,18 +282,17 @@ sig_handler process_alarm(int sig __attribute__((unused)))
   This must be first as we can't call DBUG inside an alarm for a normal thread
 */
 
-#if THR_SERVER_ALARM == THR_CLIENT_ALARM
-  if (!pthread_equal(pthread_self(),alarm_thread))
+  if (thd_lib_detected == THD_LIB_LT &&
+      !pthread_equal(pthread_self(),alarm_thread))
   {
 #if defined(MAIN) && !defined(__bsdi__)
-    printf("thread_alarm\n"); fflush(stdout);
+    printf("thread_alarm in process_alarm\n"); fflush(stdout);
 #endif
 #ifdef DONT_REMEMBER_SIGNAL
-    sigset(THR_CLIENT_ALARM,process_alarm);	/* int. thread system calls */
+    my_sigset(thr_client_alarm, process_alarm);	/* int. thread system calls */
 #endif
     return;
   }
-#endif
 
   /*
     We have to do do the handling of the alarm in a sub function,
@@ -310,7 +308,7 @@ sig_handler process_alarm(int sig __attribute__((unused)))
   process_alarm_part2(sig);
 #ifndef USE_ALARM_THREAD
 #if defined(DONT_REMEMBER_SIGNAL) && !defined(USE_ONE_SIGNAL_HAND)
-  sigset(THR_SERVER_ALARM,process_alarm);
+  my_sigset(THR_SERVER_ALARM, process_alarm);
 #endif
   pthread_mutex_unlock(&LOCK_alarm);
   pthread_sigmask(SIG_SETMASK,&old_mask,NULL);
@@ -338,7 +336,7 @@ static sig_handler process_alarm_part2(int sig __attribute__((unused)))
 	alarm_data=(ALARM*) queue_element(&alarm_queue,i);
 	alarm_data->alarmed=1;			/* Info to thread */
 	if (pthread_equal(alarm_data->thread,alarm_thread) ||
-	    pthread_kill(alarm_data->thread, THR_CLIENT_ALARM))
+	    pthread_kill(alarm_data->thread, thr_client_alarm))
 	{
 #ifdef MAIN
 	  printf("Warning: pthread_kill couldn't find thread!!!\n");
@@ -362,7 +360,7 @@ static sig_handler process_alarm_part2(int sig __attribute__((unused)))
 	alarm_data->alarmed=1;			/* Info to thread */
 	DBUG_PRINT("info",("sending signal to waiting thread"));
 	if (pthread_equal(alarm_data->thread,alarm_thread) ||
-	    pthread_kill(alarm_data->thread, THR_CLIENT_ALARM))
+	    pthread_kill(alarm_data->thread, thr_client_alarm))
 	{
 #ifdef MAIN
 	  printf("Warning: pthread_kill couldn't find thread!!!\n");
@@ -439,16 +437,13 @@ void end_thr_alarm(my_bool free_structures)
 	if (error == ETIME || error == ETIMEDOUT)
 	  break;				/* Don't wait forever */
       }
-      if (!alarm_queue.elements)
+      delete_queue(&alarm_queue);
+      alarm_aborted= 1;
+      pthread_mutex_unlock(&LOCK_alarm);
+      if (!alarm_thread_running)		/* Safety */
       {
-	delete_queue(&alarm_queue);
-	alarm_aborted= 1;
-	pthread_mutex_unlock(&LOCK_alarm);
-	if (!alarm_thread_running)		/* Safety */
-	{
-	  pthread_mutex_destroy(&LOCK_alarm);
-	  pthread_cond_destroy(&COND_alarm);
-	}
+        pthread_mutex_destroy(&LOCK_alarm);
+        pthread_cond_destroy(&COND_alarm);
       }
     }
     else
@@ -505,17 +500,15 @@ void thr_alarm_info(ALARM_INFO *info)
   ARGSUSED
 */
 
-#if THR_CLIENT_ALARM != SIGALRM || defined(USE_ALARM_THREAD)
 static sig_handler thread_alarm(int sig)
 {
 #ifdef MAIN
   printf("thread_alarm\n"); fflush(stdout);
 #endif
 #ifdef DONT_REMEMBER_SIGNAL
-  sigset(sig,thread_alarm);		/* int. thread system calls */
+  my_sigset(sig, thread_alarm);		/* int. thread system calls */
 #endif
 }
-#endif
 
 
 #ifdef HAVE_TIMESPEC_TS_SEC
@@ -916,7 +909,7 @@ static sig_handler print_signal_warning(int sig)
   printf("Warning: Got signal %d from thread %s\n",sig,my_thread_name());
   fflush(stdout);
 #ifdef DONT_REMEMBER_SIGNAL
-  sigset(sig,print_signal_warning);		/* int. thread system calls */
+  my_sigset(sig, print_signal_warning);         /* int. thread system calls */
 #endif
 #ifndef OS2
   if (sig == SIGALRM)
@@ -943,9 +936,7 @@ static void *signal_hand(void *arg __attribute__((unused)))
   sigaddset(&set,SIGINT);
   sigaddset(&set,SIGQUIT);
   sigaddset(&set,SIGTERM);
-#if THR_CLIENT_ALARM != SIGHUP
   sigaddset(&set,SIGHUP);
-#endif
 #ifdef SIGTSTP
   sigaddset(&set,SIGTSTP);
 #endif
@@ -957,7 +948,7 @@ static void *signal_hand(void *arg __attribute__((unused)))
 #endif
 #endif /* OS2 */
   printf("server alarm: %d  thread alarm: %d\n",
-	 THR_SERVER_ALARM,THR_CLIENT_ALARM);
+         THR_SERVER_ALARM, thr_client_alarm);
   DBUG_PRINT("info",("Starting signal and alarm handling thread"));
   for(;;)
   {
@@ -1029,11 +1020,11 @@ int main(int argc __attribute__((unused)),char **argv __attribute__((unused)))
   sigaddset(&set,SIGTSTP);
 #endif
   sigaddset(&set,THR_SERVER_ALARM);
-  sigdelset(&set,THR_CLIENT_ALARM);
+  sigdelset(&set, thr_client_alarm);
   (void) pthread_sigmask(SIG_SETMASK,&set,NULL);
 #ifdef NOT_USED
   sigemptyset(&set);
-  sigaddset(&set,THR_CLIENT_ALARM);
+  sigaddset(&set, thr_client_alarm);
   VOID(pthread_sigmask(SIG_UNBLOCK, &set, (sigset_t*) 0));
 #endif
 #endif /* OS2 */
@@ -1083,8 +1074,8 @@ int main(int argc __attribute__((unused)),char **argv __attribute__((unused)))
     }
   }
   pthread_mutex_unlock(&LOCK_thread_count);
-  end_thr_alarm(1);
   thr_alarm_info(&alarm_info);
+  end_thr_alarm(1);
   printf("Main_thread:  Alarms: %u  max_alarms: %u  next_alarm_time: %lu\n",
 	 alarm_info.active_alarms, alarm_info.max_used_alarms,
 	 alarm_info.next_alarm_time);
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 00bcdbf7132..43d76f28007 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -177,12 +177,6 @@ inline void reset_floating_point_exceptions()
 } /* cplusplus */
 
 
-#if defined(HAVE_LINUXTHREADS)
-#define THR_KILL_SIGNAL SIGINT
-#else
-#define THR_KILL_SIGNAL SIGUSR2		// Can't use this with LinuxThreads
-#endif
-
 #ifdef HAVE_GLIBC2_STYLE_GETHOSTBYNAME_R
 #include <sys/types.h>
 #else
@@ -465,6 +459,7 @@ pthread_cond_t COND_refresh,COND_thread_count, COND_slave_stopped,
 pthread_cond_t COND_thread_cache,COND_flush_thread_cache;
 pthread_t signal_thread;
 pthread_attr_t connection_attrib;
+static uint thr_kill_signal;
 
 #ifdef __WIN__
 #undef	 getpid
@@ -544,7 +539,7 @@ static void close_connections(void)
     DBUG_PRINT("info",("Waiting for select_thread"));
 
 #ifndef DONT_USE_THR_ALARM
-    if (pthread_kill(select_thread,THR_CLIENT_ALARM))
+    if (pthread_kill(select_thread, thr_client_alarm))
       break;					// allready dead
 #endif
     set_timespec(abstime, 2);
@@ -844,7 +839,7 @@ extern "C" sig_handler print_signal_warning(int sig)
 		      sig,my_thread_id());
   }
 #ifdef DONT_REMEMBER_SIGNAL
-  sigset(sig,print_signal_warning);		/* int. thread system calls */
+  my_sigset(sig, print_signal_warning);         /* int. thread system calls */
 #endif
 #if !defined(__WIN__) && !defined(OS2) && !defined(__NETWARE__)
   if (sig == SIGALRM)
@@ -1841,8 +1836,10 @@ static void init_signals(void)
   DBUG_ENTER("init_signals");
 
   if (test_flags & TEST_SIGINT)
-    sigset(THR_KILL_SIGNAL,end_thread_signal);
-  sigset(THR_SERVER_ALARM,print_signal_warning); // Should never be called!
+  {
+    my_sigset(thr_kill_signal, end_thread_signal);
+  }
+  my_sigset(THR_SERVER_ALARM, print_signal_warning); // Should never be called!
 
   if (!(test_flags & TEST_NO_STACKTRACE) || (test_flags & TEST_CORE_ON_SIGNAL))
   {
@@ -1877,7 +1874,7 @@ static void init_signals(void)
 #endif
   (void) sigemptyset(&set);
 #ifdef THREAD_SPECIFIC_SIGPIPE
-  sigset(SIGPIPE,abort_thread);
+  my_sigset(SIGPIPE, abort_thread);
   sigaddset(&set,SIGPIPE);
 #else
   (void) signal(SIGPIPE,SIG_IGN);		// Can't know which thread
@@ -1903,8 +1900,12 @@ static void init_signals(void)
 #endif
   sigaddset(&set,THR_SERVER_ALARM);
   if (test_flags & TEST_SIGINT)
-    sigdelset(&set,THR_KILL_SIGNAL);		// May be SIGINT
-  sigdelset(&set,THR_CLIENT_ALARM);		// For alarms
+  {
+    // May be SIGINT
+    sigdelset(&set, thr_kill_signal);
+  }
+  // For alarms
+  sigdelset(&set, thr_client_alarm);
   sigprocmask(SIG_SETMASK,&set,NULL);
   pthread_sigmask(SIG_SETMASK,&set,NULL);
   DBUG_VOID_RETURN;
@@ -1959,23 +1960,19 @@ extern "C" void *signal_hand(void *arg __attribute__((unused)))
   */
   init_thr_alarm(max_connections +
 		 global_system_variables.max_insert_delayed_threads + 10);
-#if SIGINT != THR_KILL_SIGNAL
-  if (test_flags & TEST_SIGINT)
+  if (thd_lib_detected != THD_LIB_LT && (test_flags & TEST_SIGINT))
   {
     (void) sigemptyset(&set);			// Setup up SIGINT for debug
     (void) sigaddset(&set,SIGINT);		// For debugging
     (void) pthread_sigmask(SIG_UNBLOCK,&set,NULL);
   }
-#endif
   (void) sigemptyset(&set);			// Setup up SIGINT for debug
 #ifdef USE_ONE_SIGNAL_HAND
   (void) sigaddset(&set,THR_SERVER_ALARM);	// For alarms
 #endif
 #ifndef IGNORE_SIGHUP_SIGQUIT
   (void) sigaddset(&set,SIGQUIT);
-#if THR_CLIENT_ALARM != SIGHUP
   (void) sigaddset(&set,SIGHUP);
-#endif
 #endif
   (void) sigaddset(&set,SIGTERM);
   (void) sigaddset(&set,SIGTSTP);
@@ -2237,7 +2234,6 @@ int main(int argc, char **argv)
   tzset();			// Set tzname
 
   start_time=time((time_t*) 0);
-
 #ifdef OS2
   {
     // fix timezone for daylight saving
@@ -2254,6 +2250,9 @@ int main(int argc, char **argv)
   }
 #endif
 
+  /* Set signal used to kill MySQL */
+  thr_kill_signal= thd_lib_detected == THD_LIB_LT ? SIGINT : SIGUSR2;
+
   /*
     Init mutexes for the global MYSQL_LOG objects.
     As safe_mutex depends on what MY_INIT() does, we can't init the mutexes of