added C++ header guards

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

headers/posix/nhash.h

@@ -6,6 +6,10 @@
 
 #include "pools.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct net_hash_entry	net_hash_entry;
 typedef struct net_hash		net_hash;
 typedef struct net_hash_index	net_hash_index;
@@ -37,4 +41,8 @@ net_hash *nhash_make(void);
 void *nhash_get(net_hash *, const void *key, ssize_t klen);
 void nhash_set(net_hash *, const void *, ssize_t , const void *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* OBOS_NHASH_H */

headers/posix/poll.h

@@ -7,6 +7,10 @@
 #ifndef __POLL_H
 #define __POLL_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define POLLIN   0x0001
 #define POLLPRI  0x0002   /* not used */
 #define POLLOUT  0x0004
@@ -20,5 +24,9 @@ struct pollfd {
 
 extern int poll(struct pollfd * p, int nb, int timeout);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __POLL_H */
 

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_ */