Fix build issue with nat/linux-namespaces.c.

* nat/linux-namespaces.c (setns): Rename from this ...
	(do_setns): ... to this.  Support calling setns if it exists.
	(mnsh_handle_setns): Call do_setns.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2015-07-14  Peter Bergner  <bergner@vnet.ibm.com>
+
+	* nat/linux-namespaces.c (setns): Rename from this ...
+	(do_setns): ... to this.  Support calling setns if it exists.
+	(mnsh_handle_setns): Call do_setns.
+
 2015-07-13  Yao Qi  <yao.qi@linaro.org>
 
 	* exec.c (exec_file_attach): Add period at the end of error

gdb/nat/linux-namespaces.c

@@ -34,18 +34,18 @@ int debug_linux_namespaces;
 
 /* Handle systems without setns.  */
 
-#ifndef HAVE_SETNS
-static int
-setns (int fd, int nstype)
+static inline int
+do_setns (int fd, int nstype)
 {
-#ifdef __NR_setns
+#ifdef HAVE_SETNS
+  return setns (fd, nstype);
+#elif defined __NR_setns
   return syscall (__NR_setns, fd, nstype);
 #else
   errno = ENOSYS;
   return -1;
 #endif
 }
-#endif
 
 /* Handle systems without MSG_CMSG_CLOEXEC.  */
 
@@ -495,7 +495,7 @@ mnsh_recv_message (int sock, enum mnsh_msg_type *type,
 static ssize_t
 mnsh_handle_setns (int sock, int fd, int nstype)
 {
-  int result = setns (fd, nstype);
+  int result = do_setns (fd, nstype);
 
   return mnsh_return_int (sock, result, errno);
 }