Winbind client-side cleanups.

The global winbind file descriptor can cause havoc in some situations -
particulary when it becomes 0, 1 or 2.  This patch (based on some very nice
work by Hannes Schmidt <mail@schmidt-net.via.t-online.de>) starts to recitfy
the problem by ensuring that the close-on-exec flag is set, and that we move
above 3 in the file descriptor table.

I've also decided that the PAM module can close it's pipe handle on every
request - this isn't performance-critical code.

The next step is to do the same for nss_winbind.  (But things like getent()
might get in our way there).

This also cleans up some function prototypes, puts them in just one place.

Andrew Bartlett

source/include/includes.h

@@ -762,6 +762,8 @@ extern int errno;
 
 #include "mangle.h"
 
+#include "nsswitch/winbind_client.h"
+
 /*
  * Type for wide character dirent structure.
  * Only d_name is defined by POSIX.