- Add WEBRTC_BSD as it's closer to WEBRTC_LINUX than WEBRTC_MAC

--- configure.ac.orig	2018-07-23 14:02:57 UTC
+++ configure.ac
@@ -63,6 +63,13 @@ AS_CASE(["${host}"],
          OS_LDFLAGS="-lrt -lpthread"
          HAVE_POSIX=1
         ],
+    [*-*dragonfly*|*-*bsd*],
+        [
+         OS_CFLAGS="-DWEBRTC_BSD -DWEBRTC_THREAD_RR"
+         PLATFORM_CFLAGS="-DWEBRTC_POSIX"
+         OS_LDFLAGS="-lpthread"
+         HAVE_POSIX=1
+        ],
     [*-*darwin*],
         [
          OS_CFLAGS="-DWEBRTC_MAC -DWEBRTC_THREAD_RR -DWEBRTC_CLOCK_TYPE_REALTIME"