Speaking of libpng x86 assembly, I tried removing the pkgsrc-supplied
-DPNG_NO_ASSEMBLER_CODE in the x86_64 case.  I haven't tested it, but
it and other applications which link against it, e.g. cairo, seem to
build fine.

Months ago I merged their latest amd64 assembler code into the 1.2
branch, and it passed every test I could throw at it.  I'm going to
look into this more, but I figured I'd ask some people to test it if
they could.

Regards,

--Blair