Implemented UTC_TIME, UTC_DATE and UTC_TIMESTAMP functions (WL#345)

configure.in:
  ./configure now tests if gmtime_r is present
include/config-os2.h:
  Supposing that OS/2 have gmtime_r
include/my_pthread.h:
  Use our imeplementation of gmtime_r if system lacks one
mysql-test/r/func_time.result:
  Added UTC_* functions to test
mysql-test/t/func_time.test:
  Added UTC_* functions to test
mysys/my_pthread.c:
  Our implementation of gmtime_r
mysys/my_thr_init.c:
  Now we also need LOCK_locktime_r if gmtime_r is absent
sql/item_timefunc.cc:
  Generalized classes for CURDATE, CURTIME and NOW, abstracted them from
  timezone. Added new children classes for implementing these and UTC_*
  functions.
sql/item_timefunc.h:
  Generalized classes for CURDATE, CURTIME and NOW, abstracted them from
  timezone. Added new children classes for implementing these and UTC_*
  functions.
sql/lex.h:
  Added tokens for UTC_TIME, UTC_DATE and UTC_TIMESTAMP
sql/sql_yacc.yy:
  Added UTC_* functions to grammar. Current functions are using 
  classes now.

sql/item_timefunc.h

@@ -350,6 +350,8 @@ public:
 };
 
 
+/* Abstract CURTIME function. Children should define what timezone is used */
+
 class Item_func_curtime :public Item_func
 {
   longlong value;
@@ -363,29 +365,77 @@ public:
   double val() { return (double) value; }
   longlong val_int() { return value; }
   String *val_str(String *str);
-  const char *func_name() const { return "curtime"; }
   void fix_length_and_dec();
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg)
   {
     return (new Field_time(maybe_null, name, t_arg, default_charset()));
-  }  
+  }
+  /* 
+    Abstract method that defines which time zone is used for conversion.
+    Converts time from time_t representation to broken down representation
+    in struct tm using gmtime_r or localtime_r functions.
+  */
+  virtual void store_now_in_tm(time_t now, struct tm *now_tm)=0;
 };
 
 
+class Item_func_curtime_local :public Item_func_curtime
+{
+public:
+  Item_func_curtime_local() :Item_func_curtime() {}
+  Item_func_curtime_local(Item *a) :Item_func_curtime(a) {}
+  const char *func_name() const { return "curtime"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
+};
+
+
+class Item_func_curtime_utc :public Item_func_curtime
+{
+public:
+  Item_func_curtime_utc() :Item_func_curtime() {}
+  Item_func_curtime_utc(Item *a) :Item_func_curtime(a) {}
+  const char *func_name() const { return "utc_time"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
+};
+
+
+/* Abstract CURDATE function. See also Item_func_curtime. */
+
 class Item_func_curdate :public Item_date
 {
   longlong value;
   TIME ltime;
 public:
   Item_func_curdate() :Item_date() {}
+  void set_result_from_tm(struct tm *now);
   longlong val_int() { return (value) ; }
-  const char *func_name() const { return "curdate"; }
-  void fix_length_and_dec();			/* Retrieves curtime */
+  void fix_length_and_dec();
   bool get_date(TIME *res,bool fuzzy_date);
+  virtual void store_now_in_tm(time_t now, struct tm *now_tm)=0;
 };
 
 
+class Item_func_curdate_local :public Item_func_curdate
+{
+public:
+  Item_func_curdate_local() :Item_func_curdate() {}
+  const char *func_name() const { return "curdate"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
+};
+
+
+class Item_func_curdate_utc :public Item_func_curdate
+{
+public:
+  Item_func_curdate_utc() :Item_func_curdate() {}
+  const char *func_name() const { return "utc_date"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
+};
+
+
+/* Abstract CURRENT_TIMESTAMP function. See also Item_func_curtime */
+
 class Item_func_now :public Item_date_func
 {
   longlong value;
@@ -400,9 +450,29 @@ public:
   longlong val_int() { return value; }
   int save_in_field(Field *to, bool no_conversions);
   String *val_str(String *str);
-  const char *func_name() const { return "now"; }
   void fix_length_and_dec();
   bool get_date(TIME *res,bool fuzzy_date);
+  virtual void store_now_in_tm(time_t now, struct tm *now_tm)=0;
+};
+
+
+class Item_func_now_local :public Item_func_now
+{
+public:
+  Item_func_now_local() :Item_func_now() {}
+  Item_func_now_local(Item *a) :Item_func_now(a) {}
+  const char *func_name() const { return "now"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
+};
+
+
+class Item_func_now_utc :public Item_func_now
+{
+public:
+  Item_func_now_utc() :Item_func_now() {}
+  Item_func_now_utc(Item *a) :Item_func_now(a) {}
+  const char *func_name() const { return "utc_timestamp"; }
+  void store_now_in_tm(time_t now, struct tm *now_tm);
 };