Add #define _BSD_SOURCE where mplayer is not C99.

libavfilter/libmpcodecs/vf_detc.c

@@ -16,6 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#define _BSD_SOURCE //strdup
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

libavfilter/libmpcodecs/vf_divtc.c

@@ -16,6 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#define _BSD_SOURCE //strdup
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

libavfilter/libmpcodecs/vf_palette.c

@@ -16,6 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#define _BSD_SOURCE //strcasecmp
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>