diff -ru4NwbB libpng-1.5.4/Makefile.am libpng-1.5.5beta01/Makefile.am
--- libpng-1.5.4/Makefile.am	2011-07-07 06:24:55.914993260 -0500
+++ libpng-1.5.5beta01/Makefile.am	2011-07-13 06:28:24.284107612 -0500
@@ -161,9 +161,9 @@
 	rm -f $@ dfn?.out
 	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
 	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out\
-	    logunsupported=4 - ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	    logunsupported=5 - ${srcdir}/scripts/pnglibconf.dfa 1>&2
 	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
 	rm dfn1.out
 	mv dfn2.out $@
 
diff -ru4NwbB libpng-1.5.4/contrib/pngminus/makefile.std libpng-1.5.5beta01/contrib/pngminus/makefile.std
--- libpng-1.5.4/contrib/pngminus/makefile.std	2011-07-07 06:24:48.716051405 -0500
+++ libpng-1.5.5beta01/contrib/pngminus/makefile.std	2011-07-13 06:28:08.281252003 -0500
@@ -7,11 +7,11 @@
 
 RM=rm -f
 
 #PNGPATH = /usr/local
-#PNGINC = -I$(PNGPATH)/include/libpng12
-#PNGLIB = -L$(PNGPATH)/lib -lpng12
-#PNGLIBS = $(PNGPATH)/lib/libpng12.a
+#PNGINC = -I$(PNGPATH)/include/libpng15
+#PNGLIB = -L$(PNGPATH)/lib -lpng15
+#PNGLIBS = $(PNGPATH)/lib/libpng15.a
 PNGINC = -I../..
 PNGLIB = -L../.. -lpng
 PNGLIBS = ../../libpng.a
 
@@ -22,11 +22,11 @@
 ZINC = -I../../../zlib
 ZLIB = -L../../../zlib -lz
 ZLIBS = ../../../zlib/libz.a
 
-CFLAGS=-O3 $(PNGINC) $(ZINC)
-LDFLAGS=$(PNGLIB) $(ZLIB)
-LDFLAGSS=$(PNGLIBS) $(ZLIBS)
+CFLAGS=$(PNGINC) $(ZINC)
+LDLIBS=$(PNGLIB) $(ZLIB)
+LDLIBSS=$(PNGLIBS) $(ZLIBS)
 C=.c
 O=.o
 L=.a
 E=
@@ -39,21 +39,21 @@
 png2pnm$(O): png2pnm$(C)
 	$(CC) -c $(CFLAGS) png2pnm$(C)
 
 png2pnm$(E): png2pnm$(O)
-	$(LD) -o png2pnm$(E) png2pnm$(O) $(LDFLAGS) -lm
+	$(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
 
 png2pnm-static$(E): png2pnm$(O)
-	$(LD) -o png2pnm-static$(E) png2pnm$(O) $(LDFLAGSS) -lm
+	$(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm
 
 pnm2png$(O): pnm2png$(C)
 	$(CC) -c $(CFLAGS) pnm2png$(C)
 
 pnm2png$(E): pnm2png$(O)
-	$(LD) -o pnm2png$(E) pnm2png$(O) $(LDFLAGS) -lm
+	$(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
 
 pnm2png-static$(E): pnm2png$(O)
-	$(LD) -o pnm2png-static$(E) pnm2png$(O) $(LDFLAGSS) -lm
+	$(LD) $(LDFLAGS) -o pnm2png-static$(E) pnm2png$(O) $(LDLIBSS) -lm
 
 clean:
 	$(RM) png2pnm$(O)
 	$(RM) pnm2png$(O)
diff -ru4NwbB libpng-1.5.4/png.c libpng-1.5.5beta01/png.c
--- libpng-1.5.4/png.c	2011-07-07 06:24:48.277563190 -0500
+++ libpng-1.5.5beta01/png.c	2011-07-13 06:28:07.310827364 -0500
@@ -541,10 +541,10 @@
 #  ifdef PNG_STDIO_SUPPORTED
 /* Initialize the default input/output functions for the PNG file.  If you
  * use your own read or write routines, you can call either png_set_read_fn()
  * or png_set_write_fn() instead of png_init_io().  If you have defined
- * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
- * necessarily available.
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
+ * function of your own because "FILE *" isn't necessarily available.
  */
 void PNGAPI
 png_init_io(png_structp png_ptr, png_FILE_p fp)
 {