Add support for GNU/kFreeBSD systems.

patch from Petr Salinger submitted by Sam Hocevar

Originally committed as revision 5464 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -414,6 +414,15 @@ make="gmake"
 CFLAGS="$CFLAGS -pthread"
 FFLDFLAGS="$FFLDFLAGS -export-dynamic -pthread"
 ;;
+GNU/kFreeBSD)
+v4l="no"
+v4l2="no"
+bktr="yes"
+audio_oss="yes"
+dv1394="no"
+CFLAGS="$CFLAGS -pthread"
+LDFLAGS="$LDFLAGS -rdynamic"
+;;
 BSD/OS)
 v4l="no"
 v4l2="no"

libavformat/grab_bktr.c

@@ -30,6 +30,9 @@
 #  include <machine/ioctl_meteor.h>
 #  include <machine/ioctl_bt848.h>
 # endif
+#elif defined(__FreeBSD_kernel__)
+# include <dev/bktr/ioctl_meteor.h>
+# include <dev/bktr/ioctl_bt848.h>
 #elif defined(__DragonFly__)
 # include <dev/video/meteor/ioctl_meteor.h>
 # include <dev/video/bktr/ioctl_bt848.h>