Define pass_signals[] only once such that Valgrind can be built with -fno-common. This is a modified version of the second patch attached to #273536.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11777 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_gdbserver/server.c b/coregrind/m_gdbserver/server.c
index 069d1dc..546fe3b 100644
--- a/coregrind/m_gdbserver/server.c
+++ b/coregrind/m_gdbserver/server.c
@@ -33,6 +33,8 @@
 unsigned long thread_from_wait;
 unsigned long old_thread_from_wait;
 
+int pass_signals[TARGET_SIGNAL_LAST];
+
 /* for a gdbserver integrated in valgrind, resuming the process consists
    in returning the control to valgrind.
    Then at the next error or break or ..., valgrind calls gdbserver again.