Say whether we're using X11 double buffering

* configure.ac (EMACS_CONFIG_FEATURES): Output value of HAVE_XDBE.

diff --git a/configure.ac b/configure.ac
index c44165fb5c10a26bc8f94cc101f4937fb10223c2..e1fcf1254df8c43b75df42acb82bb0dc32d1d4fe 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -6637,6 +6637,7 @@ AC_DEFINE_UNQUOTED([EMACS_CONFIG_FEATURES], ["${emacs_config_features}"],
   [Summary of some of the main features enabled by configure.])
 
 AS_ECHO(["  Does Emacs use -lXaw3d?                                 ${HAVE_XAW3D}
+  Does Emacs use X11 double buffering?                    ${HAVE_XDBE}
   Does Emacs use -lXpm?                                   ${HAVE_XPM}
   Does Emacs use -ljpeg?                                  ${HAVE_JPEG}
   Does Emacs use -ltiff?                                  ${HAVE_TIFF}