Fix debugging kfreebsd-amd64 lockup

[Hector Oron]

Hello,

  The patch is missing a changelog entry, but could you please comment
on the following code:

--- a/gdb/common/signals.c
+++ b/gdb/common/signals.c
@@ -600,6 +600,15 @@
       return SIGINFO;
 #endif

+#if defined(__GLIBC__) && defined(__FreeBSD_kernel__)
+    case TARGET_SIGNAL_LINUXTHREADS_RESTART:
+      return 32;
+    case TARGET_SIGNAL_LINUXTHREADS_CANCEL:
+      return 33;
+    case TARGET_SIGNAL_LINUXTHREADS_DEBUG:
+      return 34;
+#endif
+
     default:
 #if defined (REALTIME_LO)
       retsig = 0;

Comments from the original author, Jeff Epler can be seen at:
  <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=698200  >

Regards,
-- 
 Héctor Orón  -.. . -... .. .- -.   -.. . ...- . .-.. --- .--. . .-.