Avoid insecure usage of tmpnam in tests.

Various glibc testcases use tmpnam in ways subject to race conditions
(generate a temporary file name, then later open that file without
O_EXCL).

This patch fixes those tests to use mkstemp - generally a minimal
local fix to use mkstemp instead of tmpnam, rather than a larger fix
to use other testsuite infrastructure for temporary files.  The
unchanged use of tmpnam in posix/wordexp-test.c would fail safe in the
event of a race (it's generating a name for use with mkdir rather than
for a file to be opened for writing).

Tested for x86_64.

	* grp/tst_fgetgrent.c: Include <unistd.h>.
	(main): Use mkstemp instead of tmpnam.
	* io/test-utime.c (main): Likewise.
	* posix/annexc.c (macrofile): Change to modifiable array.
	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
	macrofile here.
	* posix/bug-getopt1.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt2.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt3.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt4.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* posix/bug-getopt5.c: Include <stdlib.h>.
	(do_test): Use mkstemp instead of tmpnam.
	* stdio-common/bug7.c: Include <stdlib.h> and <unistd.h>.
	(main): Use mkstemp instead of tmpnam.
	* stdio-common/tst-fdopen.c: Include <stdlib.h>.
	(main): Use mkstemp instead of tmpnam.
	* stdio-common/tst-ungetc.c: Include <stdlib.h>.
	(main): use mkstemp instead of tmpnam.
	* stdlib/isomac.c (macrofile): Change to modifiable array.
	(get_null_defines): Use mkstemp instead of tmpnam.  Do not remove
	macrofile here.

1 files changed, 6 insertions, 3 deletions

diff --git a/posix/bug-getopt3.c b/posix/bug-getopt3.c
index c3a8cb225b..45a8d3ec3d 100644
--- a/posix/bug-getopt3.c
+++ b/posix/bug-getopt3.c
@@ -2,6 +2,7 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 static const struct option opts[] =
   {
@@ -48,12 +49,14 @@ one_test (const char *fmt, int argc, char *argv[], int n, int expected[n],
 static int
 do_test (void)
 {
-  char *fname = tmpnam (NULL);
-  if (fname == NULL)
+  char fname[] = "/tmp/bug-getopt3.XXXXXX";
+  int fd = mkstemp (fname);
+  if (fd == -1)
     {
-      puts ("cannot generate name for temporary file");
+      printf ("mkstemp failed: %m\n");
       return 1;
     }
+  close (fd);
 
   if (freopen (fname, "w+", stderr) == NULL)
     {