Optimizer eliminated the pthread_create() call.

configure.in

@@ -266,7 +266,7 @@ dnl			AC_DEFINE(HAVE_LINUX_THREADS,1)
 				save_LIBS="$LIBS"
 				LIBS="-pthread $LIBS"
 				AC_TRY_LINK([#include <pthread.h>],[
-					if(0) pthread_create((pthread_t*) 0,
+					pthread_create((pthread_t*) 0,
 						(pthread_attr_t*) 0, 0, 0);
 					], cf_cv_pthread_flag=yes, cf_cv_pthread_flag=no)
 				dnl restore the LIBS