[PATCH] [gdb/build] Fix build on postmarketos

[Tom de Vries <tdevries@suse.de>]

I tried building gdbserver on postmarketos (which is based on alpine linux,
which uses musl libc), and ran into:
...
gdbserver/linux-low.cc: In lambda function:
gdbserver/linux-low.cc:1907:41: error: \
  'W_EXITCODE' was not declared in this scope
 1907 |               mark_lwp_dead (leader_lp, W_EXITCODE (0, 0), true);
      |                                         ^~~~~~~~~~
...

The macro W_EXITCODE is not defined in gdbsupport/gdb_wait.h, but WSETEXIT is:
...
 /* These are not defined in POSIX, but are used by our programs.  */

 #ifndef WSETEXIT
 # ifdef W_EXITCODE
 #define WSETEXIT(w,status) ((w) = W_EXITCODE(status,0))
 # else
 #define WSETEXIT(w,status) ((w) = (0 | ((status) << 8)))
 # endif
 #endif
...

Fix this by using WSETEXIT.

Tested on x86_64-linux.

PR build/31483
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31483
---
 gdbserver/linux-low.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 9d5a6242803..aaa7bbc2a4c 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -1904,7 +1904,9 @@ linux_process_target::check_zombie_leaders ()
 	  thread_info *leader_thread = get_lwp_thread (leader_lp);
 	  if (report_exit_events_for (leader_thread))
 	    {
-	      mark_lwp_dead (leader_lp, W_EXITCODE (0, 0), true);
+	      int wstat;
+	      WSETEXIT (wstat, 0);
+	      mark_lwp_dead (leader_lp, wstat, true);
 	      new_pending_event = true;
 	    }
 	  else

base-commit: 3a4c6f1aa958739705ee69526fdeed7c69d7243c
-- 
2.35.3