Add Gnulib portability modules; update Gnulib files.

* m4/gnulib-cache.m4 (gl_MODULES): Add `flock' (provides flock(2)
  declaration and implementation), `fpieee' (fixes floating point
  behavior on Alpha and SH), `stdlib' (provides an unsetenv(3)
  declaration, among others), `putenv' (provides a putenv(3) declaration
  and implementation with the semantics we need).

lib/malloc.c

@@ -0,0 +1,57 @@
+/* malloc() function that is glibc compatible.
+
+   Copyright (C) 1997, 1998, 2006, 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* written by Jim Meyering and Bruno Haible */
+
+#include <config.h>
+/* Only the AC_FUNC_MALLOC macro defines 'malloc' already in config.h.  */
+#ifdef malloc
+# define NEED_MALLOC_GNU
+# undef malloc
+#endif
+
+/* Specification.  */
+#include <stdlib.h>
+
+#include <errno.h>
+
+/* Call the system's malloc below.  */
+#undef malloc
+
+/* Allocate an N-byte block of memory from the heap.
+   If N is zero, allocate a 1-byte block.  */
+
+void *
+rpl_malloc (size_t n)
+{
+  void *result;
+
+#ifdef NEED_MALLOC_GNU
+  if (n == 0)
+    n = 1;
+#endif
+
+  result = malloc (n);
+
+#if !HAVE_MALLOC_POSIX
+  if (result == NULL)
+    errno = ENOMEM;
+#endif
+
+  return result;
+}