Bug in PNG support of latest GNU and ESP Ghostscript

GNU and ESP Ghostscript are not built with support for PNG devices, even
if so requested, because the configure script is lacking the definition of
PNG_DEVS. After I had added that, the build failed on gdevpng.c because
png_.h didn't include the libpng header at all, because the HAVE_PNG_H or
HAVE_LIBPNG_H macros are not set on the corresponding command line (in
gs.mak). I've added these flags to the variable PCF_ in gs.mak, I hope
that was the right way to do it. At least it works now.

This is my ChangeLog:

-----snip-----
2002-08-03  Sven Moritz Hallberg  <[email protected]>

	* configure.ac: Only mention Makefile in one AC_OUTPUT call.
	Add PNG_DEVS variable.
	src/gs.mak (PCF_): Add -D flags for HAVE_PNG_H and HAVE_LIBPNG_PNG_H.
-----snap-----

The diff is attached. It was made against ESP Ghostscript 7.05.3, but I
suspect it'll work unchanged for GNU Ghostscript as well. Notice that AFPL
Ghostscript, as far as I can see, should not be affected by this bug,
because the relevant parts appear to have been added by GNU.

To [email protected]: I hope you're the right person to send this patch
to, please incorporate it into the ebuild, because the missing PNG support
breaks the build for gstreamer (that's how I noticed it).


Greetings,
Sven Moritz