Reenable alloca support on ZTS

This got disabled due to an incorrect change in a preprocessor condition
in 2104bea. It was not supposed to
be disabled.

Author: nikic

Zend/zend_portability.h

@@ -355,7 +355,7 @@ char *alloca();
 
 #endif
 
-#if (HAVE_ALLOCA || (defined (__GNUC__) && __GNUC__ >= 2)) && !(defined(ZTS)) && !(defined(ZTS) && defined(HPUX)) && !defined(DARWIN)
+#if (HAVE_ALLOCA || (defined (__GNUC__) && __GNUC__ >= 2)) && !(defined(ZTS) && defined(HPUX)) && !defined(DARWIN)
 # define ZEND_ALLOCA_MAX_SIZE (32 * 1024)
 # define ALLOCA_FLAG(name) \
 	zend_bool name;