ax_check_gd

Check for the gd library. (See http://www.boutell.com/gd/) If gd is found, the output variables GD_CFLAGS, GD_LDFLAGS and GD_LIBS will contain the compiler flags, linker flags and libraries necessary to use gd; otherwise, those variables will be empty. In addition, the symbol HAVE_GD is defined if the library is found, and the symbols HAVE_GD_GIF, HAVE_GD_JPEG and HAVE_GD_PNG are defined if the lirbary supports creating images in gif, jpeg and png formats, respectively.

The user may use --with-gd=no or --without-gd to skip checking for the library. (The default is --with-gd=yes.) If the library is installed in an unusual location, --with-gd=DIR will cause the macro to look for gdlib-config in DIR/bin or, failing that, for the headers and libraries in DIR/include and DIR/lib.

Feedback welcome!

AC_DEFUN([AX_CHECK_GD], [
        AC_ARG_WITH(gd,
                AC_HELP_STRING([--with-gd(=DIR)], [use the gd library (in DIR)]),,
                with_gd=yes)

        if test "$with_gd" != no; then
                AC_PATH_PROG(GDLIB_CONFIG, gdlib-config, , [$with_gd/bin:$PATH])
                if test -n "$GDLIB_CONFIG"; then
                        GD_CFLAGS=`$GDLIB_CONFIG --cflags`
                        GD_LDFLAGS=`$GDLIB_CONFIG --ldflags`
                        GD_LIBS=`$GDLIB_CONFIG --libs`
                elif test -d "$with_gd"; then
                        GD_CFLAGS="-I$with_gd/include"
                        GD_LDFLAGS="-L$with_gd/lib"
                        AC_CHECK_LIB(z, inflateReset, GD_LIBS="-lz")
                        AC_CHECK_LIB(png, png_check_sig, GD_LIBS="-lpng $GD_LIBS", , $GD_LIBS)
                fi

                save_CFLAGS="$CFLAGS"
                CFLAGS="$GD_CFLAGS $CFLAGS"
                save_LDFLAGS="$LDFLAGS"
                LDFLAGS="$GD_LDFLAGS $LDFLAGS"

                AC_CHECK_LIB(gd, gdImageCreate, [
                        AC_DEFINE(HAVE_GD, 1, [ Define if you have gd library. ])
                        AC_CHECK_LIB(gd, gdImageGif, AC_DEFINE(HAVE_GD_GIF, 1, [ Define if GD supports gif. ]), , "$GD_LIBS")
                        AC_CHECK_LIB(gd, gdImageJpeg, AC_DEFINE(HAVE_GD_JPEG, 1, [ Define if GD supports jpeg. ]), , "$GD_LIBS")
                        AC_CHECK_LIB(gd, gdImagePng, AC_DEFINE(HAVE_GD_PNG, 1, [ Define if GD supports png. ]), , "$GD_LIBS")
                        GD_LIBS="-lgd $GD_LIBS"
                ], with_gd=no, $GD_LIBS)

                CFLAGS="$save_CFLAGS"
                LDFLAGS="$save_LDFLAGS"
        fi

        if test "$with_gd" = "no"; then
                GD_CFLAGS="";
                GD_LDFLAGS="";
                GD_LIBS="";
        fi

        AC_SUBST(GD_CFLAGS)
        AC_SUBST(GD_LDFLAGS)
        AC_SUBST(GD_LIBS)
])

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.