r300g: advertise S3TC only when it's available in Gallium

src/gallium/drivers/r300/r300_texture.c

@@ -24,6 +24,7 @@
 #include "pipe/p_screen.h"
 
 #include "util/u_format.h"
+#include "util/u_format_s3tc.h"
 #include "util/u_math.h"
 #include "util/u_memory.h"
 
@@ -170,6 +171,10 @@ uint32_t r300_translate_texformat(enum pipe_format format,
 
     /* S3TC formats. */
     if (desc->layout == UTIL_FORMAT_LAYOUT_S3TC) {
+        if (!util_format_s3tc_enabled) {
+            return ~0; /* Unsupported. */
+        }
+
         switch (format) {
             case PIPE_FORMAT_DXT1_RGB:
             case PIPE_FORMAT_DXT1_RGBA: