contrib: png: don't build binaries

contrib/src/png/bins.patch

+--- png/Makefile.am.orig	2013-08-20 14:05:04.803159380 +0200
++++ png/Makefile.am	2013-08-20 14:05:10.795159128 +0200
+@@ -7,10 +7,10 @@
+ ACLOCAL_AMFLAGS = -I scripts
+ 
+ # test programs - run on make check, make distcheck
+-check_PROGRAMS= pngtest pngunknown pngstest pngvalid
++check_PROGRAMS= 
+ 
+ # Utilities - installed
+-bin_PROGRAMS= pngfix png-fix-itxt
++bin_PROGRAMS= 
+ 
+ pngtest_SOURCES = pngtest.c
+ pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la

contrib/src/png/rules.mak

@@ -15,6 +15,7 @@ $(TARBALLS)/libpng-$(PNG_VERSION).tar.xz:
 png: libpng-$(PNG_VERSION).tar.xz .sum-png
 	$(UNPACK)
 	$(APPLY) $(SRC)/png/winrt.patch
+	$(APPLY) $(SRC)/png/bins.patch
 	$(MOVE)
 
 DEPS_png = zlib $(DEPS_zlib)