From dce6957d863500b2e9d6912353c3c9fa0dc7485a Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Wed, 23 Oct 2024 15:41:08 +0200
Subject: [PATCH] configure.ac: Fix FIONREAD check with gcc-14 on Solaris

Before this fix, it would fail to build with gcc-14 with the error:
conftest.c: In function 'main':
conftest.c:265:11: error: implicit declaration of function 'ioctl'
 [-Wimplicit-function-declaration]
  265 | int foo = ioctl (0, FIONREAD, &foo);
      |           ^~~~~

Solaris documents ioctl() as being defined in <unistd.h>.

* configure.ac: Fix FIONREAD check with gcc-14 on Solaris.
Ref:
https://lists.gnu.org/r/emacs-devel/2024-10/msg00195.html

Copyright-paperwork-exempt: yes
(cherry picked from commit 5e5689a2a40cd16d7593a0c7ddea5511adc3bf22)
---
 configure.ac | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/configure.ac b/configure.ac
index 0540d18b142..c49bc0e80d6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7150,6 +7150,9 @@ AC_CACHE_CHECK([for usable FIONREAD], [emacs_cv_usable_FIONREAD],
 			    #ifdef USG5_4
 			    # include <sys/filio.h>
 			    #endif
+			    #ifdef HAVE_UNISTD_H
+			    # include <unistd.h> /* defines ioctl() on Solaris */
+			    #endif
 			  ]],
 			  [[int foo = ioctl (0, FIONREAD, &foo);]])],
 	 [emacs_cv_usable_FIONREAD=yes],
-- 
2.39.5