cocoa: Suppress Cocoa window with -display

Do not open a Cocoa window when another display is selected that will be
initialized later. The Cocoa display cannot be selected with -display,
so there is no need to check its argument.

Signed-off-by: Rainer Müller <raimue@codingfarm.de>
Reviewed-by: Andreas Färber <andreas.faerber@web.de>
Message-id: 1441807710-25431-1-git-send-email-raimue@codingfarm.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

ui/cocoa.m

diff --git a/ui/cocoa.m b/ui/cocoa.m
index 334e6f6..c24d9f9 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -1148,6 +1148,7 @@
                 !strcmp(opt, "-nographic") ||
                 !strcmp(opt, "-version") ||
                 !strcmp(opt, "-curses") ||
+                !strcmp(opt, "-display") ||
                 !strcmp(opt, "-qtest")) {
                 return qemu_main(gArgc, gArgv, *_NSGetEnviron());
             }