diff --git a/build.config.common b/build.config.common
index 57e04fdb5e1a..3106a149adf6 100644
--- a/build.config.common
+++ b/build.config.common
@@ -8,7 +8,7 @@ CLANG_PREBUILT_BIN=prebuilts/clang/host/linux-x86/clang-${CLANG_VERSION}/bin
 BUILDTOOLS_PREBUILT_BIN=build/kernel/build-tools/path/linux-x86
 DTC=${ROOT_DIR}/${BUILDTOOLS_PREBUILT_BIN}/dtc
 
-KCFLAGS=-D__ANDROID_COMMON_KERNEL__
+KCFLAGS="${KCFLAGS} -D__ANDROID_COMMON_KERNEL__"
 EXTRA_CMDS=''
 STOP_SHIP_TRACEPRINTK=1
 IN_KERNEL_MODULES=1