diff --git a/core/clang/config.mk b/core/clang/config.mk
index 00815e4..756bf49 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -1,7 +1,7 @@
 ## Clang configurations.
 
-LLVM_PREBUILTS_VERSION := 3.8
-LLVM_PREBUILTS_BASE := prebuilts/clang/host
+LLVM_PREBUILTS_VERSION ?= 3.8
+LLVM_PREBUILTS_BASE ?= prebuilts/clang/host
 LLVM_PREBUILTS_PATH := $(LLVM_PREBUILTS_BASE)/$(BUILD_OS)-x86/$(LLVM_PREBUILTS_VERSION)/bin
 LLVM_RTLIB_PATH := $(LLVM_PREBUILTS_PATH)/../lib/clang/$(LLVM_PREBUILTS_VERSION)/lib/linux/