diff --git a/build.config.common b/build.config.common
index e7d0b3e0003f..9ec1c637a79f 100644
--- a/build.config.common
+++ b/build.config.common
@@ -7,7 +7,7 @@ DTC=dtc
 CLANG_PREBUILT_BIN=prebuilts-master/clang/host/linux-x86/clang-r416183b/bin
 BUILDTOOLS_PREBUILT_BIN=build/build-tools/path/linux-x86
 
-KCFLAGS=-D__ANDROID_COMMON_KERNEL__
+KCFLAGS="${KCFLAGS} -D__ANDROID_COMMON_KERNEL__"
 EXTRA_CMDS=''
 STOP_SHIP_TRACEPRINTK=1
 IN_KERNEL_MODULES=1