putenv.c: avoid conflicting types for 'unsetenv' on FreeBSD.

[Jim Meyering]

I've just committed this:
[coreutils-6.8 needs this patch on FreeBSD]

        Avoid conflicting types for 'unsetenv' on FreeBSD.
        * lib/putenv.c (_unsetenv): Rename from "unsetenv", to avoid
        conflicting with FreeBSD's (5.0 and 6.1) function declaration
        in stdlib.h.

Index: lib/putenv.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/putenv.c,v
retrieving revision 1.33
diff -u -p -r1.33 putenv.c
--- lib/putenv.c        21 Feb 2007 07:54:16 -0000      1.33
+++ lib/putenv.c        25 Feb 2007 00:47:12 -0000
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991, 1994, 1997, 1998, 2000, 2003, 2004, 2005, 2006
+/* Copyright (C) 1991, 1994, 1997, 1998, 2000, 2003, 2004, 2005, 2006, 2007
    Free Software Foundation, Inc.

    NOTE: The canonical source of this file is maintained with the GNU C
@@ -57,7 +57,7 @@ __libc_lock_define_initialized (static,
 #endif

 static int
-unsetenv (const char *name)
+_unsetenv (const char *name)
 {
   size_t len;
   char **ep;
@@ -105,7 +105,7 @@ rpl_putenv (const char *string)
   if (name_end == NULL)
     {
       /* Remove the variable from the environment.  */
-      return unsetenv (string);
+      return _unsetenv (string);
     }

   size = 0;