SourceMod can now be somewhat compiled on OS X for patch sanity testing (bug 3516, r=ds).

This adds the ability for us to change the GCC version we use more flexibly.

extensions/clientprefs/sdk/smsdk_ext.cpp

@@ -30,7 +30,7 @@
  */
 
 #include <stdio.h>
-#include <malloc.h>
+#include <stdlib.h>
 #include "smsdk_ext.h"
 
 /**
@@ -434,7 +434,7 @@ bool SDKExtension::SDK_OnMetamodPauseChange(bool paused, char *error, size_t max
 #endif
 
 /* Overload a few things to prevent libstdc++ linking */
-#if defined __linux__
+#if defined __linux__ || defined __APPLE__
 extern "C" void __cxa_pure_virtual(void)
 {
 }
@@ -459,3 +459,4 @@ void operator delete[](void * ptr)
 	free(ptr);
 }
 #endif
+