package/gdb: fix gdb-7.12.1 build on xtensa

This fixes the following gdb-7.12.1 build error on xtensa architecture:

  gdb/xtensa-linux-nat.c: In function 'void fetch_gregs(regcache*, ptid_t, int)':
  gdb/xtensa-linux-nat.c:178:23: error: uninitialized const 'regs' [-fpermissive]
     const gdb_gregset_t regs;

Backported from: d274ecf4ddf76768af57e27f654b9ce6784b391c
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gdb/7.12.1/0001-Remove-const-in-xtensa-linux-nat.c-fetch_gregs.patch

@@ -0,0 +1,39 @@
+From d274ecf4ddf76768af57e27f654b9ce6784b391c Mon Sep 17 00:00:00 2001
+From: Simon Marchi <simon.marchi@ericsson.com>
+Date: Mon, 6 Mar 2017 16:06:42 -0500
+Subject: [PATCH] Remove const in xtensa-linux-nat.c:fetch_gregs
+
+Fixes:
+
+/home/emaisin/src/binutils-gdb/gdb/xtensa-linux-nat.c: In function 'void fetch_gregs(regcache*, ptid_t, int)':
+/home/emaisin/src/binutils-gdb/gdb/xtensa-linux-nat.c:178:23: error: uninitialized const 'regs' [-fpermissive]
+   const gdb_gregset_t regs;
+                       ^
+
+gdb/ChangeLog:
+
+	* xtensa-linux-nat.c (fetch_gregs): Remove const.
+
+Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
+---
+Backported from: d274ecf4ddf76768af57e27f654b9ce6784b391c
+
+ gdb/xtensa-linux-nat.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/gdb/xtensa-linux-nat.c b/gdb/xtensa-linux-nat.c
+index afe15f6..c29f0c7 100644
+--- a/gdb/xtensa-linux-nat.c
++++ b/gdb/xtensa-linux-nat.c
+@@ -175,7 +175,7 @@ static void
+ fetch_gregs (struct regcache *regcache, int regnum)
+ {
+   int tid = ptid_get_lwp (inferior_ptid);
+-  const gdb_gregset_t regs;
++  gdb_gregset_t regs;
+   int areg;
+   
+   if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
+-- 
+2.1.4
+