system doesn't install a pngconf.h appropriate to the options passed to the
build.
So we have to put a PNG_NO_ASSEMBLER_CODE define into pngconf.h manually.
This unbreaks (at least) ImageMagick on amd64.
Some more information about this problem can be found here:
http://sourceforge.net/mailarchive/forum.php?thread_id=10314069&forum_id=43850
Since we don't want to compile pentium specific code,
remove -DPNG_USE_PNGGCCRD.
Bump major lib version and PKGNAME.
with help & ok steven@, naddy@