configure: log libpng-config details and fix libs setup

This way we can see what script it tried to use as well as the flags
it got back from that script.

This also fixes the libs lookup to use --ldflags instead of --libs
as the former includes -L flags.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Get rid of msinttypes folder and replace it with compile error if fixed-width integers are not available (fixes #73)
Revert "Get rid of msinttypes folder and replace it with compile error if fixed-width integers are not available (fixes #73)"

This reverts commit 4feac0a10e9edb350e8946f1503c729a4501a8f4.
Add msinttypes/ folder to EXTRA_DIST (fixes #73)
gdImageCreateFromWebpCtx new implementation proposal, fix issue #75
improves a08a17ddafd0
use 4k for allocation step
seems simpler...
prepare 2.1.0 final
Create gd.h from gd.h.in to properly include current library version
Don't append dash when GDLIB_EXTRA is empty
Merged in fix-version-in-gd.h (pull request #9)

Create gd.h from gd.h.in to properly include current library version
ignore generated gd.h header
Add INSTALL notes for Solaris conflicting iconv.h headers (fixes #76)
GD_EXTRA_VERSION and GD_VERSION_STRING needs quotes (Courtesy of Marc Deslauriers)
fix #81, cmake_minimum_required must be the 1st line in 2.8+