diff --git a/Makefile b/Makefile
index 6aaf834..9acba9d 100644
--- a/Makefile
+++ b/Makefile
@@ -103,13 +103,13 @@ MANPAGES_HTML = $(addsuffix .html,$(MANPAGES))
 .DEFAULT_GOAL := compton
 
 src/.clang_complete: Makefile
-	@(for i in $(filter-out -O% -DNDEBUG, $(CFG) $(CFLAGS) $(INCS)); do echo "$$i"; done) > $@
+	@(for i in $(filter-out -O% -DNDEBUG, $(CFG) $(CPPFLAGS) $(CFLAGS) $(INCS)); do echo "$$i"; done) > $@
 
 %.o: src/%.c src/%.h src/common.h
-	$(CC) $(CFG) $(CFLAGS) $(INCS) -c src/$*.c
+	$(CC) $(CFG) $(CPPFLAGS) $(CFLAGS) $(INCS) -c src/$*.c
 
 compton: $(OBJS)
-	$(CC) $(CFG) $(LDFLAGS) $(CFLAGS) -o $@ $(OBJS) $(LIBS)
+	$(CC) $(CFG) $(CPPFLAGS) $(LDFLAGS) $(CFLAGS) -o $@ $(OBJS) $(LIBS)
 
 man/%.1: man/%.1.asciidoc
 	a2x --format manpage $<