Fixes for building MySQL with gcc 3.0
Added SIGNED / UNSIGNED casts
Fixed core dump bug in net_clear() with libmysqld.
Back to using semaphores in query cache.
Added 'Null' and 'Index_type' to SHOW INDEX.
Added new operators to be used with gcc 3.0.x
Update of query cache code.
Added semaphores for Windows (not yet in use)
Added pthread_mutex_trylock for windows.
Changed some sql_alloc() -> thd->alloc()
Removed a lot of compiler warnings on Linux Alpha (64 bit)
Fixed some core dumps on 64 bit systems (wrong type for packet_len)