emacs-29 5f3b46c61e2: * configure.ac: Include X11/Xlib.h for XOpenDisplay. (Bug#68842)

[Ulrich Müller]

branch: emacs-29
commit 5f3b46c61e23786295e8e532f7eadeee8cd4340b
Author: Ulrich Müller <ulm@gentoo.org>
Commit: Ulrich Müller <ulm@gentoo.org>

    * configure.ac: Include X11/Xlib.h for XOpenDisplay.  (Bug#68842)
    
    Do not merge to master.
---
 configure.ac | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 78d5475f75a..34a5a89bea9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2697,7 +2697,7 @@ if test "${HAVE_X11}" = "yes"; then
 
   if test "${opsys}" = "gnu-linux"; then
     AC_CACHE_CHECK([whether X on GNU/Linux needs -b to link], 
[emacs_cv_b_link],
-    [AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
+    [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <X11/Xlib.h>]],
      [[XOpenDisplay ("foo");]])],
      [xgnu_linux_first_failure=no],
      [xgnu_linux_first_failure=yes])
@@ -2706,7 +2706,7 @@ if test "${HAVE_X11}" = "yes"; then
       OLD_LIBS="$LIBS"
       CPPFLAGS="$CPPFLAGS -b i486-linuxaout"
       LIBS="$LIBS -b i486-linuxaout"
-      AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
+      AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <X11/Xlib.h>]],
        [[XOpenDisplay ("foo");]])],
        [xgnu_linux_second_failure=no],
        [xgnu_linux_second_failure=yes])