[devel]  Moved libpng-config.in and libpng.pc-configure.in out of the scripts

    directory, to libpng-config.in and libpng-pc.in, respectively, and
    modified Makefile.am and configure.ac accordingly.  Now "configure"
    needs nothing from the "scripts" directory.
  Also, avoid redefining PNG_CONST in pngconf.h
7 files changed