os: Make OsSignalHandler ask for core dumps for signo != SIGQUIT

SIGQUIT is a normal termination request, but any other signal we handle
here wants a core. This has the effect of making FatalError's call to
AbortServer trigger the

    if (CoreDump)
        OsAbort();

path. This will allow us to remove some DDX code that has the same net
effect.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>

os/osinit.c

@@ -52,6 +52,7 @@ SOFTWARE.
 #include <X11/X.h>
 #include "os.h"
 #include "osdep.h"
+#include "opaque.h"
 #include <X11/Xos.h>
 #include <signal.h>
 #include <errno.h>
@@ -74,8 +75,6 @@ SOFTWARE.
 #define ADMPATH "/usr/adm/X%smsgs"
 #endif
 
-extern char *display;
-
 #ifdef RLIMIT_DATA
 int limitDataSpace = -1;
 #endif
@@ -151,6 +150,9 @@ OsSigHandler(int signo)
     }
 #endif
 
+    if (signo != SIGQUIT)
+        CoreDump = TRUE;
+
     FatalError("Caught signal %d (%s). Server aborting\n",
                signo, strsignal(signo));
 }