--- Makefile	2013-02-26 01:03:50.000000000 +0100
+++ Makefile	2013-05-19 09:24:50.001314584 +0200
@@ -12,13 +12,20 @@
 # Alternatively, build libpng in this directory:
 CUSTOMLIBPNG ?= ../libpng
 
-CFLAGSOPT ?= -DNDEBUG -O3 -fstrict-aliasing -ffast-math -funroll-loops -fomit-frame-pointer -ffinite-math-only
+CFLAGSSYS := $(CFLAGS)
+LDFLAGSSYS := $(LDFLAGS)
 
-CFLAGS ?= -Wall -Wno-unknown-pragmas -I. -I$(CUSTOMLIBPNG) -I/usr/local/include/ -I/usr/include/ -I/usr/X11/include/ $(CFLAGSOPT)
-CFLAGS += -std=c99 $(CFLAGSADD)
+CFLAGSOPT ?= -DNDEBUG -O3 -fstrict-aliasing -ffast-math -funroll-loops
+CFLAGSOPT += -fomit-frame-pointer -ffinite-math-only
+CFLAGSOPT += -Wall -Wno-unknown-pragmas -I. -I$(CUSTOMLIBPNG) -I$(CUSTOMZLIB)
+CFLAGSOPT += -I/usr/local/include/ -I/usr/include/ -I/usr/X11/include/
+CFLAGSOPT += -std=c99 
 
-LDFLAGS ?= -L$(CUSTOMLIBPNG) -L/usr/local/lib/ -L/usr/lib/ -L/usr/X11/lib/
-LDFLAGS += -lpng -lm $(LDFLAGSADD)
+LDFLAGSOPT ?= -L$(CUSTOMLIBPNG) -L/usr/local/lib/ -L/usr/lib/ -L/usr/X11/lib/
+LDFLAGSOPT += -lpng -lm 
+
+CFLAGS = $(CFLAGSOPT) $(CFLAGSADD) $(CFLAGSSYS)
+LDFLAGS = $(LDFLAGSOPT) $(LDFLAGSADD) $(LDFLAGSSYS)
 
 OBJS = pngquant.o rwpng.o pam.o mediancut.o blur.o mempool.o viter.o nearest.o
 COCOA_OBJS = rwpng_cocoa.o
@@ -28,7 +35,7 @@
 TARFILE = $(TARNAME)-src.tar.bz2
 
 ifdef USE_COCOA
-CFLAGS += -DUSE_COCOA=1
+CFLAGSOPT += -DUSE_COCOA=1
 OBJS += $(COCOA_OBJS)
 FRAMEWORKS += -framework Cocoa
 endif