os: utils: drop unused VENDORSUPPORT

This doesn't seem to be used anymore for two decades now,
so there's probably no need to keep it any longer.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1518>

hw/xfree86/common/xf86Init.c

@@ -856,13 +856,8 @@ ddxGiveUp(enum ExitCode error)
 void
 OsVendorFatalError(const char *f, va_list args)
 {
-#ifdef VENDORSUPPORT
-    ErrorFSigSafe("\nPlease refer to your Operating System Vendor support "
-                 "pages\nat %s for support on this crash.\n", VENDORSUPPORT);
-#else
     ErrorFSigSafe("\nPlease consult the " XVENDORNAME " support \n\t at "
                  __VENDORDWEBSUPPORT__ "\n for help. \n");
-#endif
     if (xf86LogFile && xf86LogFileWasOpened)
         ErrorFSigSafe("Please also check the log file at \"%s\" for additional "
                      "information.\n", xf86LogFile);

os/utils.c

@@ -1463,9 +1463,7 @@ enum BadCode {
     InternalError
 };
 
-#if defined(VENDORSUPPORT)
-#define BUGADDRESS VENDORSUPPORT
-#elif defined(BUILDERADDR)
+#if defined(BUILDERADDR)
 #define BUGADDRESS BUILDERADDR
 #else
 #define BUGADDRESS "xorg@freedesktop.org"