Update libpng from 1.6.3 to 1.6.10

Change-Id: I76e81e7fd267d15991cd342c5caeb2fe77964ebf
diff --git a/scripts/makefile.netbsd b/scripts/makefile.netbsd
index 9448c75..af4eb93 100644
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -2,7 +2,7 @@
 # make obj && make depend && make && make test
 # make includes && make install
 # Copyright (C) 2002 Patrick R.L. Welche
-# Copyright (C) 2007-2009 Glenn Randers-Pehrson
+# Copyright (C) 2007-2009, 2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
@@ -17,7 +17,7 @@
 
 LIB=	png
 SHLIB_MAJOR=	16
-SHLIB_MINOR=	1.6.3
+SHLIB_MINOR=	1.6.10
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
@@ -34,6 +34,9 @@
 
 CLEANFILES+=pngtest.o pngtest pnglibconf.h
 
+.c.o:
+	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
+
 # see scripts/pnglibconf.mak for more options
 pnglibconf.h: scripts/pnglibconf.h.prebuilt
 	cp scripts/pnglibconf.h.prebuilt $@