Fix some minor races in hosts lacking mkostemp.

Gnulib's emulation of mkostemp doesn't have races that Emacs's does.
* configure.ac (mkostemp): Remove check for this function;
gnulib does the check now.
(mkstemp): Remove check for this no-longer-used function.
* lib/mkostemp.c, lib/secure_getenv.c, lib/tempname.c, lib/tempname.h:
* m4/mkostemp.m4, m4/secure_getenv.m4, m4/tempname.m4:
New files, copied from Gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* admin/merge-gnulib (GNULIB_MODULES): Add mkostemp.
* lib-src/movemail.c (main):
* lib-src/update-game-score.c (write_scores):
Use mkostemp (which now works on all platforms, due to changes
in the portability layer) rather than mktemp (which has a race)
or mkstemp (which we no longer bother with).
* src/callproc.c (create_temp_file):
* src/filelock.c (create_lock_file):
Assume mkostemp, since it's now provided by Gnulib.

Fixes: debbugs:15015

1 files changed, 23 insertions, 0 deletions

diff --git a/m4/mkostemp.m4 b/m4/mkostemp.m4
new file mode 100644
index 00000000000..6d101eeda39
--- /dev/null
+++ b/m4/mkostemp.m4
@@ -0,0 +1,23 @@
+# mkostemp.m4 serial 2
+dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MKOSTEMP],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  dnl Persuade glibc <stdlib.h> to declare mkostemp().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([mkostemp])
+  if test $ac_cv_func_mkostemp != yes; then
+    HAVE_MKOSTEMP=0
+  fi
+])
+
+# Prerequisites of lib/mkostemp.c.
+AC_DEFUN([gl_PREREQ_MKOSTEMP],
+[
+])