added C++ header guards

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@1680 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/posix/resolv.h

@@ -98,6 +98,10 @@
 #include <sys/socket.h>
 #include <stdio.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*
  * Revision information.  This is the release date in YYYYMMDD format.
  * It can change every day so the right thing to do with it is use it
@@ -346,4 +350,8 @@ int		res_queriesmatch (const uchar *, const uchar *,
 				      const uchar *, const uchar *);
 void		res_close (void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* !_RESOLV_H_ */