Bug#52514: mysql 5.1 do_abi_check does not compile w/ gcc4.5

due to GCC preprocessor change
      
The problem is that newer GCC versions treats missing headers
as fatal errors. The solution is to use a guard macro to prevent
the inclusion of system headers when checking the ABI with the
C Preprocessor.

Reference: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15638
           http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44836

include/mysql.h.pp

@@ -1,4 +1,3 @@
-#include <sys/types.h>
 typedef char my_bool;
 typedef int my_socket;
 #include "mysql_version.h"