diff -Nuarp zlib-1.2.7-ori/win32/Makefile.gcc zlib-1.2.7/win32/Makefile.gcc
--- zlib-1.2.7-ori/win32/Makefile.gcc	2012-05-02 20:17:58.000000000 +0200
+++ zlib-1.2.7/win32/Makefile.gcc	2012-07-04 23:19:10.747624677 +0200
@@ -41,15 +41,15 @@ SHARED_MODE=0
 #LOC = -DASMV
 #LOC = -DDEBUG -g
 
-PREFIX =
+PREFIX = i686-w64-mingw32-
 CC = $(PREFIX)gcc
-CFLAGS = $(LOC) -O3 -Wall
+CFLAGS = $(LOC) -O2 -march=i686 -mtune=generic -pipe -fomit-frame-pointer -Wall
 
 AS = $(CC)
 ASFLAGS = $(LOC) -Wall
 
 LD = $(CC)
-LDFLAGS = $(LOC)
+LDFLAGS = $(LOC) -Wl,-O1 -Wl,--as-needed
 
 AR = $(PREFIX)ar
 ARFLAGS = rcs