+###############################################################################
+#
+# Check for -lpng
+#
+###############################################################################
+
+have_png=no
+with_png_req=unspecified
+png_halfassed=no
+
+# Check whether --with-png was given.
+if test "${with_png+set}" = set; then :
+ withval=$with_png; with_png="$withval"; with_png_req="$withval"
+else
+ with_png=yes
+fi
+
+
+
+ case "$with_png" in
+ yes) ;;
+ no) ;;
+
+ /*)
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PNG headers" >&5
+$as_echo_n "checking for PNG headers... " >&6; }
+ d=$with_png/include
+ if test -d $d; then
+ X_CFLAGS="-I$d $X_CFLAGS"
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $d" >&5
+$as_echo "$d" >&6; }
+ else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: not found ($d: no such directory)" >&5
+$as_echo "not found ($d: no such directory)" >&6; }
+ fi
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PNG libs" >&5
+$as_echo_n "checking for PNG libs... " >&6; }
+ d=$with_png/lib
+ if test -d $d; then
+ X_LIBS="-L$d $X_LIBS"
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $d" >&5
+$as_echo "$d" >&6; }
+ else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: not found ($d: no such directory)" >&5
+$as_echo "not found ($d: no such directory)" >&6; }
+ fi
+
+ # replace the directory string with "yes".
+ with_png_req="yes"
+ with_png=$with_png_req
+ ;;
+
+ *)
+ echo ""
+ echo "error: argument to --with-png must be \"yes\", \"no\", or a directory."
+ echo " If it is a directory, then \`DIR/include' will be added to"
+ echo " the -I list, and \`DIR/lib' will be added to the -L list."
+ exit 1
+ ;;
+ esac
+
+
+if test "$with_png" != yes -a "$with_png" != no ; then
+ echo "error: must be yes or no: --with-png=$with_png"
+ exit 1
+fi
+
+if test "$with_png" = yes; then
+
+ have_png=no
+
+ ac_save_CPPFLAGS="$CPPFLAGS"
+ if test \! -z "$includedir" ; then
+ CPPFLAGS="$CPPFLAGS -I$includedir"
+ fi
+ CPPFLAGS="$CPPFLAGS $X_CFLAGS"
+ CPPFLAGS=`eval eval eval eval eval eval eval eval eval echo $CPPFLAGS`
+ ac_fn_c_check_header_mongrel "$LINENO" "png.h" "ac_cv_header_png_h" "$ac_includes_default"
+if test "x$ac_cv_header_png_h" = xyes; then :
+ have_png=yes
+fi
+
+
+ CPPFLAGS="$ac_save_CPPFLAGS"
+
+ if test "$have_png" = yes; then
+ # we have the header, now check for the library
+ have_png=no
+ png_halfassed=yes
+
+ ac_save_CPPFLAGS="$CPPFLAGS"
+ ac_save_LDFLAGS="$LDFLAGS"
+# ac_save_LIBS="$LIBS"
+
+ if test \! -z "$includedir" ; then
+ CPPFLAGS="$CPPFLAGS -I$includedir"
+ fi
+ # note: $X_CFLAGS includes $x_includes
+ CPPFLAGS="$CPPFLAGS $X_CFLAGS"
+
+ if test \! -z "$libdir" ; then
+ LDFLAGS="$LDFLAGS -L$libdir"
+ fi
+ # note: $X_LIBS includes $x_libraries
+ LDFLAGS="$LDFLAGS $X_LIBS $X_EXTRA_LIBS"
+
+ CPPFLAGS=`eval eval eval eval eval eval eval eval eval echo $CPPFLAGS`
+ LDFLAGS=`eval eval eval eval eval eval eval eval eval echo $LDFLAGS`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for png_create_read_struct in -lpng" >&5
+$as_echo_n "checking for png_create_read_struct in -lpng... " >&6; }
+if ${ac_cv_lib_png_png_create_read_struct+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpng $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char png_create_read_struct ();
+int
+main ()
+{
+return png_create_read_struct ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_png_png_create_read_struct=yes
+else
+ ac_cv_lib_png_png_create_read_struct=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_png_png_create_read_struct" >&5
+$as_echo "$ac_cv_lib_png_png_create_read_struct" >&6; }
+if test "x$ac_cv_lib_png_png_create_read_struct" = xyes; then :
+ have_png=yes
+ png_halfassed=no
+ PNG_LIBS="-lpng"
+ $as_echo "#define HAVE_LIBPNG 1" >>confdefs.h
+
+fi
+
+ CPPFLAGS="$ac_save_CPPFLAGS"
+ LDFLAGS="$ac_save_LDFLAGS"
+# LIBS="$ac_save_LIBS"
+
+ fi
+fi
+
+