diff --git a/Makefile.libcompat b/Makefile.libcompat
--- a/Makefile.libcompat
+++ b/Makefile.libcompat
@@ -25,9 +25,9 @@
 # Don't rebuild build-tools targets during normal build.
 LIB${_LIBCOMPAT}WMAKEENV+=	BUILD_TOOLS_META=.NOMETA
 .endif
-LIB${_LIBCOMPAT}WMAKEFLAGS+= CC="${XCC} ${LIB${_LIBCOMPAT}CFLAGS}" \
-		CXX="${XCXX} ${LIB${_LIBCOMPAT}CXXFLAGS} ${LIB${_LIBCOMPAT}CFLAGS}" \
-		CPP="${XCPP} ${LIB${_LIBCOMPAT}CFLAGS}" \
+LIB${_LIBCOMPAT}WMAKEFLAGS+= CC="${XCC} ${LIB${_LIBCOMPAT}CFLAGS:@v@${v:Q}@}" \
+		CXX="${XCXX} ${LIB${_LIBCOMPAT}CXXFLAGS:@v@${v:Q}@} ${LIB${_LIBCOMPAT}CFLAGS:@v@${v:Q}@}" \
+		CPP="${XCPP} ${LIB${_LIBCOMPAT}CFLAGS:@v@${v:Q}@}" \
 		DESTDIR=${WORLDTMP} \
 		-DNO_CPU_CFLAGS \
 		MK_BOOT=no \