[m-rev.] diff: fix compilation of extras/net on OS X

[Julien Fischer]

Fix compilation of extras/net on OS X.

extras/net/netdb.m:
     The function getprotobyname_r is a GNU extension and isn't available
     on systems that don't use the GNU libc (not just Windows).

Julien.

diff --git a/extras/net/netdb.m b/extras/net/netdb.m
index d20340f..328c08f 100644
--- a/extras/net/netdb.m
+++ b/extras/net/netdb.m
@@ -1,12 +1,12 @@
  %-----------------------------------------------------------------------------%
  % vim: ft=mercury ts=4 sw=4 et
  %---------------------------------------------------------------------------%
-% Copyright (C) 2014 The Mercury Team
+% Copyright (C) 2014-2015 The Mercury Team
  % This file may only be copied under the terms of the GNU Library General
  % Public License - see the file COPYING.LIB
  %-----------------------------------------------------------------------------%
  %
-% Module: netdb 
+% Module: netdb
  % Main Author:  Paul Bone <paul at bone.id.au>
  % Stability:    low
  %
@@ -17,8 +17,8 @@
  %
  %-----------------------------------------------------------------------------%
  %-----------------------------------------------------------------------------%
-:- module net.netdb.

+:- module net.netdb.
  :- interface.

  :- import_module io.
@@ -151,7 +151,10 @@ getprotobyname(Name, MaybeProtocol, !IO) :-
          Found::out, _IO0::di, _IO::uo),
      [will_not_call_mercury, promise_pure, thread_safe, tabled_for_io],
  "
-#ifndef MR_WIN32
+/*
+** getprotobyname_r is a GNU extension.
+*/
+#if defined(__GNU_LIBRARY__)

      int result;
      struct protoent *temp = MR_GC_NEW(struct protoent);
@@ -166,9 +169,9 @@ getprotobyname(Name, MaybeProtocol, !IO) :-
      int             num_aliases;
      int             i;

-#ifdef MR_THREAD_SAFE
-    MR_LOCK(lookup_lock, ""getprotobyname_r"");
-#endif
+    #ifdef MR_THREAD_SAFE
+      MR_LOCK(lookup_lock, ""getprotobyname_r"");
+    #endif

      temp = getprotobyname(Name);
      if (temp != NULL) {
@@ -187,11 +190,11 @@ getprotobyname(Name, MaybeProtocol, !IO) :-
      }
      Success = MR_YES;

-#ifdef MR_THREAD_SAFE
-    MR_UNLOCK(lookup_lock, ""getprotobyname_r"");
-#endif
+    #ifdef MR_THREAD_SAFE
+      MR_UNLOCK(lookup_lock, ""getprotobyname_r"");
+    #endif

-#endif /* RM_WIN32 */
+#endif /* ! __GNU_LIBRARY__ */
  ").

  %-----------------------------------------------------------------------------%