--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@
 API_MINOR = 1
 API_PATCH = 0
 
-CFLAGS := -std=gnu99 -D_FILE_OFFSET_BITS=64 -Wall -Wextra -O3 -ffast-math -g -MMD $(CFLAGS)
+CFLAGS := -std=gnu99 -D_FILE_OFFSET_BITS=64 -Wall -Wextra -ffast-math -MMD $(CFLAGS) $(CPPFLAGS)
 
 PREFIX ?= /usr/local
 BINDIR ?= $(PREFIX)/bin