diff --git a/util/xcompile/xcompile b/util/xcompile/xcompile
index ff067d2f6a..3948811782 100755
--- a/util/xcompile/xcompile
+++ b/util/xcompile/xcompile
@@ -260,13 +260,20 @@ fi
 cat <<EOF
 
 # Clang
-CLANG_CC_${TARCH}:=${CLANG}
-CLANG_CFLAGS_${TARCH}:=${CFLAGS_CLANG}
-CLANG_CFLAGS_${TARCH}+=-Qunused-arguments -m${TWIDTH}
+CLANG_CC_${TARCH} := ${CLANG}
+CLANG_CFLAGS_${TARCH} := ${CFLAGS_CLANG}
+CLANG_CFLAGS_${TARCH} += -Qunused-arguments
+CLANG_CFLAGS_${TARCH} += -m${TWIDTH}
 # tone down clang compiler warnings
-CLANG_CFLAGS_${TARCH}+=-Wno-unused-variable -Wno-unused-function -Wno-tautological-compare
-CLANG_CFLAGS_${TARCH}+=-Wno-shift-overflow -Wno-address-of-packed-member -Wno-initializer-overrides
-CLANG_CFLAGS_${TARCH}+=-fbracket-depth=2048 -mllvm -asm-macro-max-nesting-depth=1000
+CLANG_CFLAGS_${TARCH} += -Wno-unused-variable
+CLANG_CFLAGS_${TARCH} += -Wno-unused-function
+CLANG_CFLAGS_${TARCH} += -Wno-tautological-compare
+CLANG_CFLAGS_${TARCH} += -Wno-shift-overflow
+CLANG_CFLAGS_${TARCH} += -Wno-address-of-packed-member
+CLANG_CFLAGS_${TARCH} += -Wno-initializer-overrides
+CLANG_CFLAGS_${TARCH} += -fbracket-depth=2048
+CLANG_CFLAGS_${TARCH} += -mllvm
+CLANG_CFLAGS_${TARCH} += -asm-macro-max-nesting-depth=1000
 CLANG_COMPILER_RT_${TARCH}:=${CC_RT_CLANG}
 CLANG_COMPILER_RT_FLAGS_${TARCH}:=${CC_RT_EXTRA_CLANG}
 # Leak the target arch into the preprocessor flags with clang.