Recent change to xfns.c breaks compilation

[Markus Rost <rost@math.ohio-state.edu>]

   This change:

   2003-07-12  Richard M. Stallman  <rms@bogus.example.com>

	   * xfns.c: Include libpng/png.h instead of png.h.

   causes problems on my GNU/Linux system (redhat 6.2) where png.h is in
   /usr/include.

   What is the rationale for that change?


   Since configure only checks for the presence of png.h (and not
   libpng/png.h), I think we need to check for both and condition the
   #include with HAVE_PNG_H and HAVE_LIBPNG_PNG_H.

It still breaks compilation for me, on gnu/linux and solaris.
Moreover autoconf does not work well after the recent change

2003-07-12  Richard M. Stallman  <rms@gnu.org>

	* configure.in [netbsd systems]: Define HAVE_CRTIN properly.

Here are some lines from the shell:

gcc -c -D_BSD_SOURCE   -Demacs -DHAVE_CONFIG_H -DUSE_LUCID  -I. -I/home/rost/cvs-gnu-linux1/emacs/src -D_BSD_SOURCE -I/usr/X11R6/include -g xfns.c
xfns.c:7568:24: libpng/png.h: No such file or directory
make[1]: *** [xfns.o] Error 1
make[1]: Leaving directory `/home/rost/cvs-gnu-linux1/emacs/src'
make: *** [bootstrap] Error 2

euler:~/cvs-gnu-linux1/emacs> autoconf
configure.in:50: error: possibly undefined macro: AC_DEFINE
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.

euler:~/cvs-gnu-linux1/emacs> autoconf --version
autoconf (GNU Autoconf) 2.57

euler:~/cvs-gnu-linux1/emacs> configure
checking build system type... i686-pc-linux-gnu
checking host system type... i686-pc-linux-gnu
./configure: line 1666: syntax error near unexpected token `AC_DEFINE(HAVE_CRTIN)'
./configure: line 1666: `      AC_DEFINE(HAVE_CRTIN)'