Add some missing feature macro definitions.

Building with -ansi failed due to some code (as well as system
headers) using non-C89 features. Fix that by adding the usual
_POSIX_SOURCE and _BSD_SOURCE definitions already present in some
other files.

libvncserver/sockets.c

@@ -41,6 +41,11 @@
  *  USA.
  */
 
+#ifdef __STRICT_ANSI__
+#define _BSD_SOURCE
+#define _POSIX_SOURCE
+#endif
+
 #include <rfb/rfb.h>
 
 #ifdef LIBVNCSERVER_HAVE_SYS_TYPES_H

libvncserver/websockets.c

@@ -26,6 +26,11 @@
  *  USA.
  */
 
+#ifdef __STRICT_ANSI__
+#define _BSD_SOURCE
+#define _POSIX_SOURCE
+#endif
+
 #include <rfb/rfb.h>
 #include <resolv.h> /* __b64_ntop */
 /* errno */