diff --git a/libavfilter/libmpcodecs/vf_detc.c b/libavfilter/libmpcodecs/vf_detc.c
index 8122233de2..83e09dd71e 100644
--- a/libavfilter/libmpcodecs/vf_detc.c
+++ b/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>
diff --git a/libavfilter/libmpcodecs/vf_divtc.c b/libavfilter/libmpcodecs/vf_divtc.c
index 5cc9932feb..0b6ea04a6c 100644
--- a/libavfilter/libmpcodecs/vf_divtc.c
+++ b/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>
diff --git a/libavfilter/libmpcodecs/vf_palette.c b/libavfilter/libmpcodecs/vf_palette.c
index 45fc41ba45..3a7f0869bf 100644
--- a/libavfilter/libmpcodecs/vf_palette.c
+++ b/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>