[PATCH] Fix compiler warning in linux-namespaces.c

["Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>]

../../gdb/nat/linux-namespaces.c: In function ‘void mnsh_main(int)’:
../../gdb/nat/linux-namespaces.c:604:8: warning: ‘fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  close (fd);
  ~~~~~~^~~~

And the warning is correct -- mnsh_recv_message can return -1 and leave fd
uninitialized, and mnsh_main will still call close (fd) if that happens.

Initialize fd to -1 to avoid that.

gdb/ChangeLog:

2019-08-27  Christian Biesinger  <cbiesinger@google.com>

	* nat/linux-namespaces.c (mnsh_main): Initialize fd (to -1).
---
 gdb/nat/linux-namespaces.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c
index 503f755903..57843cda36 100644
--- a/gdb/nat/linux-namespaces.c
+++ b/gdb/nat/linux-namespaces.c
@@ -562,14 +562,14 @@ mnsh_main (int sock)
   while (1)
     {
       enum mnsh_msg_type type;
-      int fd, int1, int2;
+      int fd = -1, int1, int2;
       char buf[PATH_MAX];
       ssize_t size, response = -1;
 
       size = mnsh_recv_message (sock, &type,
 				&fd, &int1, &int2,
 				buf, sizeof (buf));
-
+`
       if (size >= 0 && size < sizeof (buf))
 	{
 	  switch (type)
-- 
2.23.0.187.g17f5b7556c-goog