add clang option to makefile

Makefile

@@ -4,8 +4,9 @@ REGENERATE_BINDINGS = no
 HEADERS = ../godot_headers
 TARGET = debug
 NAME = godot-cpp
+USE_CLANG = no
 
-BASE = scons n=$(NAME) regenerate_bindings=$(REGENERATE_BINDINGS) target=$(TARGET) headers=$(HEADERS) godotbinpath=$(GODOT_BIN_PATH) -j4
+BASE = scons n=$(NAME) use_llvm=$(USE_CLANG) regenerate_bindings=$(REGENERATE_BINDINGS) target=$(TARGET) headers=$(HEADERS) godotbinpath=$(GODOT_BIN_PATH) -j4
 LINUX = $(BASE) p=linux
 WINDOWS = $(BASE) p=windows
 OSX = $(BASE) p=osx