ct_driver: define XMODE_'s if not defined yet

Traditionally they've been defined in Xorg server headers, but since this
driver seems to be the only consumer, it makes sense moving them here.
(and later drop them from xorg headers)

Explicitly guarding it, so it also works with xorg headers version still
carrying those symbols.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/driver/xf86-video-chips/-/merge_requests/6>

src/ct_driver.c

@@ -131,6 +131,14 @@
 /* Driver specific headers */
 #include "ct_driver.h"
 
+/* traditionally these had been defined in xf86_OSlib.h */
+#ifndef XMODE_RGB
+#define XMODE_RGB   0
+#define XMODE_NTSC  1
+#define XMODE_PAL   2
+#define XMODE_SECAM 3
+#endif
+
 /* Mandatory functions */
 static const OptionInfoRec *	CHIPSAvailableOptions(int chipid, int busid);
 static void     CHIPSIdentify(int flags);