avcodec/options_table: leave xvidmmx AVOption in place

Also mark it as deprecated through its help text
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/options_table.h

@@ -224,9 +224,7 @@ static const AVOption avcodec_options[] = {
 {"ipp", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_IPP }, INT_MIN, INT_MAX, V|E|D, "idct"},
 #endif /* FF_API_UNUSED_MEMBERS */
 {"xvid", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_XVID }, INT_MIN, INT_MAX, V|E|D, "idct"},
-#if FF_API_IDCT_XVIDMMX
-{"xvidmmx", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_XVID }, INT_MIN, INT_MAX, V|E|D, "idct"},
-#endif /* FF_API_IDCT_XVIDMMX */
+{"xvidmmx", "deprecated, for compatibility only", 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_XVID }, INT_MIN, INT_MAX, V|E|D, "idct"},
 {"faani", "floating point AAN IDCT", 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_FAAN }, INT_MIN, INT_MAX, V|D|E, "idct"},
 {"simpleauto", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_IDCT_SIMPLEAUTO }, INT_MIN, INT_MAX, V|E|D, "idct"},
 {"slice_count", NULL, OFFSET(slice_count), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},