avfilter/vf_xmedian: Define OFFSET, FLAGS macros unconditionally

They are currently defined inside the #if CONFIG_XMEDIAN_FILTER
block. Fixes standalone compilation of the tmedian filter.
Broken in f58939affe.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/vf_xmedian.c

@@ -60,6 +60,10 @@ typedef struct XMedianContext {
     int (*median_frames)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
 } XMedianContext;
 
+#define OFFSET(x) offsetof(XMedianContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
+#define TFLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
+
 static const enum AVPixelFormat pixel_fmts[] = {
     AV_PIX_FMT_GRAY8,
     AV_PIX_FMT_GRAY9,
@@ -361,10 +365,6 @@ static av_cold int xmedian_init(AVFilterContext *ctx)
     return init(ctx);
 }
 
-#define OFFSET(x) offsetof(XMedianContext, x)
-#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
-#define TFLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
-
 static const AVOption xmedian_options[] = {
     { "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=3},  3, 255, .flags = FLAGS },
     { "planes", "set planes to filter", OFFSET(planes),    AV_OPT_TYPE_INT, {.i64=15}, 0,  15, .flags =TFLAGS },