os: drop unneeded DDXOSVERRORF conditional

This conditional practically only controls whether we have an pointer,
where DDX can plug in it's own VErrorF() handler (currently only xwin
doing that). The cost of having it even when DDX doesn't use it, is
really negligible: it's just one pointer and an extra non-null check
on it per VErrorF() call - a very cold path. Strangely, xwin has extra

Getting rid of this unnecessary complexity that really hasn't any
practical gain.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1329>

os/log.c

@@ -104,9 +104,7 @@ OR PERFORMANCE OF THIS SOFTWARE.
 #pragma clang diagnostic ignored "-Wformat-nonliteral"
 #endif
 
-#ifdef DDXOSVERRORF
 void (*OsVendorVErrorFProc) (const char *, va_list args) = NULL;
-#endif
 
 /* Default logging parameters. */
 #ifndef DEFAULT_LOG_VERBOSITY
@@ -1036,14 +1034,10 @@ FatalError(const char *f, ...)
 void
 VErrorF(const char *f, va_list args)
 {
-#ifdef DDXOSVERRORF
     if (OsVendorVErrorFProc)
         OsVendorVErrorFProc(f, args);
     else
         LogVWrite(-1, f, args);
-#else
-    LogVWrite(-1, f, args);
-#endif
 }
 
 void