From d8ddf1307aec129f1e8da74ee0be01dd83f86c0d Mon Sep 17 00:00:00 2001
From: Lauri Nurmi <lanurmi@iki.fi>
Date: Thu, 24 Feb 2022 17:51:44 +0200
Subject: [PATCH] Fix compilation on recent FreeBSDs by ignoring <sys/epoll.h>

On recent FreeBSDs, the "Linux-only" <sys/epoll.h> exists in the default
include path, and is thus detected by configure. However, the header belongs
to the epoll-shim emulation library, and it is doubtful whether using it
on FreeBSD is a good idea. Therefore check that the operating system
is actually Linux before enabling wxEpollDispatcher.

Closes #22146.
---
 configure    | 10 +++++++++-
 configure.in | 11 ++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index e3a87f8cca..f1132b8694 100755
--- a/configure
+++ b/configure
@@ -35642,8 +35642,16 @@ fi
 done
 
             if test "$ac_cv_header_sys_epoll_h" = "yes"; then
-                $as_echo "#define wxUSE_EPOLL_DISPATCHER 1" >>confdefs.h
+                                                case "${host}" in
+                *-*-linux*)
+                    $as_echo "#define wxUSE_EPOLL_DISPATCHER 1" >>confdefs.h
 
+                ;;
+                *)
+                    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: wxEpollDispatcher disabled, because OS is not Linux" >&5
+$as_echo "$as_me: WARNING: wxEpollDispatcher disabled, because OS is not Linux" >&2;}
+                ;;
+                esac
             else
                 { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: sys/epoll.h not available, wxEpollDispatcher disabled" >&5
 $as_echo "$as_me: WARNING: sys/epoll.h not available, wxEpollDispatcher disabled" >&2;}
diff --git a/configure.in b/configure.in
index 9fed41a9ae..16ff78cc72 100644
--- a/configure.in
+++ b/configure.in
@@ -6254,7 +6254,16 @@ if test "$wxUSE_CONSOLE_EVENTLOOP" = "yes"; then
         if test "$wxUSE_EPOLL_DISPATCHER" = "yes"; then
             AC_CHECK_HEADERS(sys/epoll.h,,, [AC_INCLUDES_DEFAULT()])
             if test "$ac_cv_header_sys_epoll_h" = "yes"; then
-                AC_DEFINE(wxUSE_EPOLL_DISPATCHER)
+                dnl On FreeBSD or other *BSD sys/epoll.h may exist, but require
+                dnl linking with extra libraries, so we use epoll on Linux only.
+                case "${host}" in
+                *-*-linux*)
+                    AC_DEFINE(wxUSE_EPOLL_DISPATCHER)
+                ;;
+                *)
+                    AC_MSG_WARN([wxEpollDispatcher disabled, because OS is not Linux])
+                ;;
+                esac
             else
                 AC_MSG_WARN([sys/epoll.h not available, wxEpollDispatcher disabled])
             fi