+###############################################################################
+#
+# Check for the XF86VMODE server extension (for gamma fading.)
+#
+###############################################################################
+
+have_xf86gamma=no
+with_xf86gamma_req=unspecified
+# Check whether --with-xf86gamma-ext or --without-xf86gamma-ext was given.
+if test "${with_xf86gamma_ext+set}" = set; then
+ withval="$with_xf86gamma_ext"
+ with_xf86gamma="$withval"; with_xf86gamma_req="$withval"
+else
+ with_xf86gamma=yes
+fi
+
+
+
+ case "$with_xf86gamma" in
+ yes) ;;
+ no) ;;
+
+ /*)
+ echo $ac_n "checking for xf86gamma headers""... $ac_c" 1>&6
+echo "configure:4925: checking for xf86gamma headers" >&5
+ d=$with_xf86gamma/include
+ if test -d $d; then
+ X_CFLAGS="-I$d $X_CFLAGS"
+ echo "$ac_t""$d" 1>&6
+ else
+ echo "$ac_t""not found ($d: no such directory)" 1>&6
+ fi
+
+ echo $ac_n "checking for xf86gamma libs""... $ac_c" 1>&6
+echo "configure:4935: checking for xf86gamma libs" >&5
+ d=$with_xf86gamma/lib
+ if test -d $d; then
+ X_LIBS="-L$d $X_LIBS"
+ echo "$ac_t""$d" 1>&6
+ else
+ echo "$ac_t""not found ($d: no such directory)" 1>&6
+ fi
+
+ # replace the directory string with "yes".
+ with_xf86gamma_req="yes"
+ with_xf86gamma=$with_xf86gamma_req
+ ;;
+
+ *)
+ echo ""
+ echo "error: argument to --with-xf86gamma-ext 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 "$with_xf86gamma" = yes; then
+
+ # first check for xf86vmode.h, if we haven't already
+ if test "$have_xf86vmode" = yes; then
+ have_xf86gamma=yes
+ else
+
+ ac_save_CPPFLAGS="$CPPFLAGS"
+ if test \! -z "$includedir" ; then
+ CPPFLAGS="$CPPFLAGS -I$includedir"
+ fi
+ CPPFLAGS="$CPPFLAGS $X_CFLAGS"
+ ac_safe=`echo "X11/extensions/xf86vmode.h" | sed 'y%./+-%__p_%'`
+echo $ac_n "checking for X11/extensions/xf86vmode.h""... $ac_c" 1>&6
+echo "configure:4973: checking for X11/extensions/xf86vmode.h" >&5
+if eval "test \"`echo '$''{'ac_cv_header_$ac_safe'+set}'`\" = set"; then
+ echo $ac_n "(cached) $ac_c" 1>&6
+else
+ cat > conftest.$ac_ext <<EOF
+#line 4978 "configure"
+#include "confdefs.h"
+#include <X11/extensions/xf86vmode.h>
+EOF
+ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
+{ (eval echo configure:4983: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
+if test -z "$ac_err"; then
+ rm -rf conftest*
+ eval "ac_cv_header_$ac_safe=yes"
+else
+ echo "$ac_err" >&5
+ echo "configure: failed program was:" >&5
+ cat conftest.$ac_ext >&5
+ rm -rf conftest*
+ eval "ac_cv_header_$ac_safe=no"
+fi
+rm -f conftest*
+fi
+if eval "test \"`echo '$ac_cv_header_'$ac_safe`\" = yes"; then
+ echo "$ac_t""yes" 1>&6
+ have_xf86gamma=yes
+else
+ echo "$ac_t""no" 1>&6
+fi
+
+ CPPFLAGS="$ac_save_CPPFLAGS"
+ fi
+
+ # if that succeeded, then check for the -lXxf86vm
+ if test "$have_xf86gamma" = yes; then
+ have_xf86gamma=no
+
+ ac_save_CPPFLAGS="$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"
+
+ echo $ac_n "checking for XF86VidModeSetGamma in -lXxf86vm""... $ac_c" 1>&6
+echo "configure:5028: checking for XF86VidModeSetGamma in -lXxf86vm" >&5
+ac_lib_var=`echo Xxf86vm'_'XF86VidModeSetGamma | sed 'y%./+-%__p_%'`
+if eval "test \"`echo '$''{'ac_cv_lib_$ac_lib_var'+set}'`\" = set"; then
+ echo $ac_n "(cached) $ac_c" 1>&6
+else
+ ac_save_LIBS="$LIBS"
+LIBS="-lXxf86vm -lXext -lX11 $LIBS"
+cat > conftest.$ac_ext <<EOF
+#line 5036 "configure"
+#include "confdefs.h"
+/* Override any gcc2 internal prototype to avoid an error. */
+/* We use char because int might match the return type of a gcc2
+ builtin and then its argument prototype would still apply. */
+char XF86VidModeSetGamma();
+
+int main() {
+XF86VidModeSetGamma()
+; return 0; }
+EOF
+if { (eval echo configure:5047: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+ rm -rf conftest*
+ eval "ac_cv_lib_$ac_lib_var=yes"
+else
+ echo "configure: failed program was:" >&5
+ cat conftest.$ac_ext >&5
+ rm -rf conftest*
+ eval "ac_cv_lib_$ac_lib_var=no"
+fi
+rm -f conftest*
+LIBS="$ac_save_LIBS"
+
+fi
+if eval "test \"`echo '$ac_cv_lib_'$ac_lib_var`\" = yes"; then
+ echo "$ac_t""yes" 1>&6
+ have_xf86gamma=yes
+else
+ echo "$ac_t""no" 1>&6
+true
+fi
+
+ CPPFLAGS="$ac_save_CPPFLAGS"
+ LDFLAGS="$ac_save_LDFLAGS"
+# LIBS="$ac_save_LIBS"
+
+ fi
+
+ # pull in the lib, if we haven't already
+ if test "$have_xf86gamma" = yes -a "$have_xf86vmode" = no; then
+ SAVER_LIBS="$SAVER_LIBS -lXxf86vm"
+ fi
+
+ # if that succeeded, then we've really got it.
+ if test "$have_xf86gamma" = yes; then
+ cat >> confdefs.h <<\EOF
+#define HAVE_XF86VMODE_GAMMA 1
+EOF
+
+ fi
+
+elif test "$with_xf86gamma" != no; then
+ echo "error: must be yes or no: --with-xf86gamma-ext=$with_xf86vmode"
+ exit 1
+fi
+
+