Added preliminary support for Left 4 Dead; some things may not yet work.

core/systems/ExtensionSys.cpp

@@ -69,11 +69,13 @@ CLocalExtension::CLocalExtension(const char *filename)
 		path, 
 		PLATFORM_MAX_PATH, 
 #if defined METAMOD_PLAPI_VERSION
-#if defined ORANGEBOX_BUILD
+#if SOURCE_ENGINE == SE_LEFT4DEAD
+		"extensions/auto.2.l4d/%s",
+#elif SOURCE_ENGINE == SE_ORANGEBOX
 		"extensions/auto.2.ep2/%s",
 #else
 		"extensions/auto.2.ep1/%s",
-#endif //ORANGEBOX_BUILD
+#endif //SOURCE_ENGINE == SE_LEFT4DEAD
 #else  //METAMOD_PLAPI_VERSION
 		"extensions/auto.1.ep1/%s",
 #endif //METAMOD_PLAPI_VERSION

core/systems/PluginSys.h

@@ -47,7 +47,9 @@
 #include "sm_trie.h"
 #include "sourcemod.h"
 #include <IRootConsoleMenu.h>
-#if defined ORANGEBOX_BUILD
+#if SOURCE_ENGINE == SE_LEFT4DEAD
+#include "convar_sm_l4d.h"
+#elif SOURCE_ENGINE == SE_ORANGEBOX
 #include "convar_sm_ob.h"
 #else
 #include "convar_sm.h"