diff --git a/Makefile b/Makefile
index 6bc164e4..cc2f55d6 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,12 @@ PNGLDFLAGS	:= `${PKG_CONFIG} --static --libs-only-L libpng`
 PNGLDLIBS	:= `${PKG_CONFIG} --static --libs-only-l libpng`
 
 WARNFLAGS	:= -Wall -Werror
-CFLAGS		:= ${WARNFLAGS} -g -std=c99 -D_POSIX_C_SOURCE=200809L -Iinclude
+
+# Overridable CFLAGS
+CFLAGS		:= -g
+# Non-overridable CFLAGS
+REALCFLAGS	:= ${CFLAGS} ${WARNFLAGS} -std=c99 -D_POSIX_C_SOURCE=200809L \
+		   -Iinclude
 
 YFLAGS		:=
 LFLAGS		:= --nounistd
@@ -77,16 +82,16 @@ rgbgfx_obj := \
 	src/extern/err.o
 
 rgbasm: ${rgbasm_obj}
-	$Q${CC} ${CFLAGS} -o $@ ${rgbasm_obj} -lm
+	$Q${CC} ${REALCFLAGS} -o $@ ${rgbasm_obj} -lm
 
 rgblink: ${rgblink_obj}
-	$Q${CC} ${CFLAGS} -o $@ ${rgblink_obj}
+	$Q${CC} ${REALCFLAGS} -o $@ ${rgblink_obj}
 
 rgbfix: ${rgbfix_obj}
-	$Q${CC} ${CFLAGS} -o $@ ${rgbfix_obj}
+	$Q${CC} ${REALCFLAGS} -o $@ ${rgbfix_obj}
 
 rgbgfx: ${rgbgfx_obj}
-	$Q${CC} ${CFLAGS} ${PNGLDFLAGS} -o $@ ${rgbgfx_obj} ${PNGLDLIBS}
+	$Q${CC} ${REALCFLAGS} ${PNGLDFLAGS} -o $@ ${rgbgfx_obj} ${PNGLDLIBS}
 
 # Rules to process files
 
@@ -96,11 +101,11 @@ rgbgfx: ${rgbgfx_obj}
 .l.o:
 	$Q${RM} $*.c
 	$Q${LEX} ${LFLAGS} -o $*.c $<
-	$Q${CC} ${CFLAGS} -c -o $@ $*.c
+	$Q${CC} ${REALCFLAGS} -c -o $@ $*.c
 	$Q${RM} $*.c
 
 .c.o:
-	$Q${CC} ${CFLAGS} ${PNGCFLAGS} -c -o $@ $<
+	$Q${CC} ${REALCFLAGS} ${PNGCFLAGS} -c -o $@ $<
 
 # Target used to remove all files generated by other Makefile targets.