--- a/media/mtransport/third_party/nICEr/src/util/mbslen.c
+++ b/media/mtransport/third_party/nICEr/src/util/mbslen.c
@@ -38,17 +38,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 
 #include <errno.h>
 #include <csi_platform.h>
 
 #include <assert.h>
 #include <locale.h>
 #include <stdlib.h>
 #include <wchar.h>
-#if defined(DARWIN) || defined(__FreeBSD__)
+#if defined(DARWIN) || defined(__DragonFly__) || defined(__FreeBSD__)
 #define HAVE_XLOCALE
 #endif
 
 #ifdef HAVE_XLOCALE
 #include <xlocale.h>
 #endif /* HAVE_XLOCALE */
 
 #include "nr_api.h"