--- sxiv-1.1/Makefile
+++ sxiv-1.1/Makefile
@@ -3,9 +3,8 @@
 PREFIX    = /usr/local
 MANPREFIX = $(PREFIX)/share/man
 
-CC      = gcc
-CFLAGS  = -std=c99 -Wall -pedantic -O2 -I$(PREFIX)/include -DHAVE_GIFLIB
-LDFLAGS = -L$(PREFIX)/lib
+CC      ?= gcc
+CFLAGS  += -std=c99 -Wall -pedantic -DHAVE_GIFLIB
 LIBS    = -lX11 -lImlib2 -lgif
 
 SRC = commands.c exif.c image.c main.c options.c thumbs.c util.c window.c