[COMMIT PATCH] [GDBserver] Fix gdb.threads/siginfo-threads.exp, gdb.base/siginfo-obj.exp regressions.

[Pedro Alves <palves at redhat dot com>]

This fixes the regressions reported at
<http://sourceware.org/ml/gdb-patches/2013-06/msg00280.html>:

 $ runtest-gdbserver gdb.base/siginfo-obj.exp gdb.base/siginfo-thread.exp gdb.threads/siginfo-threads.exp
 Running ./gdb.base/siginfo-thread.exp ...
 FAIL: gdb.base/siginfo-thread.exp: p ssi_addr
 Running ./gdb.threads/siginfo-threads.exp ...
 FAIL: gdb.threads/siginfo-threads.exp: signal 0 si_pid
 FAIL: gdb.threads/siginfo-threads.exp: signal 1 si_pid
 FAIL: gdb.threads/siginfo-threads.exp: signal 2 si_pid
 FAIL: gdb.threads/siginfo-threads.exp: signal 3 si_pid
 Running ./gdb.base/siginfo-obj.exp ...
 FAIL: gdb.base/siginfo-obj.exp: p ssi_addr
 FAIL: gdb.base/siginfo-obj.exp: p ssi_addr

The multi-arch patch made GDBserver do the the wrong siginfo layout
conversion, because most uses of `linux_is_elf64' were removed, and it
ended up never set.  A global really is the wrong thing to use as
elf64-ness is a per-process property; `linux_is_elf64' was just
accidentally left behind.

Tested on x86_64 Fedora 17.

gdb/gdbserver/
2013-06-12  Pedro Alves  <palves@redhat.com>

	* linux-x86-low.c (linux_is_elf64): Delete global.
	(x86_siginfo_fixup): Replace reference to `linux_is_elf64' global
	with local linux_pid_exe_is_elf_64_file use.
---
 gdb/gdbserver/linux-x86-low.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index eeedb7c..3a4f007 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -1138,8 +1138,6 @@ siginfo_from_compat_x32_siginfo (siginfo_t *to,
     }
 }
 
-/* Is this process 64-bit?  */
-static int linux_is_elf64;
 #endif /* __x86_64__ */
 
 /* Convert a native/host siginfo object, into/from the siginfo in the
@@ -1152,6 +1150,10 @@ static int
 x86_siginfo_fixup (siginfo_t *native, void *inf, int direction)
 {
 #ifdef __x86_64__
+  unsigned int machine;
+  int tid = lwpid_of (get_thread_lwp (current_inferior));
+  int is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
+
   /* Is the inferior 32-bit?  If so, then fixup the siginfo object.  */
   if (!is_64bit_tdesc ())
     {
@@ -1166,7 +1168,7 @@ x86_siginfo_fixup (siginfo_t *native, void *inf, int direction)
       return 1;
     }
   /* No fixup for native x32 GDB.  */
-  else if (!linux_is_elf64 && sizeof (void *) == 8)
+  else if (!is_elf64 && sizeof (void *) == 8)
     {
       if (sizeof (siginfo_t) != sizeof (compat_x32_siginfo_t))
 	fatal ("unexpected difference in siginfo");