[COMMITTED] posix: Fix segfault in maybe_script_execute

[Adhemerval Zanella]

This patch is essentially 28669f86f6 adjusted for the generic
implementation.

Checked on x86_64-linux-gnu with Linux spawni.c removed.  The only
failure is posix/tst-spawn3, which is expected.

	[BZ #23913]
	* sysdeps/posix/spawni.c (maybe_script_execute):
	Increment size of new_argv by one.
---
 ChangeLog              | 6 ++++++
 sysdeps/posix/spawni.c | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/sysdeps/posix/spawni.c b/sysdeps/posix/spawni.c
index c42fbd590e..c02171cc61 100644
--- a/sysdeps/posix/spawni.c
+++ b/sysdeps/posix/spawni.c
@@ -68,7 +68,7 @@ maybe_script_execute (struct posix_spawn_args *args)
       ptrdiff_t argc = args->argc;
 
       /* Construct an argument list for the shell.  */
-      char *new_argv[argc + 1];
+      char *new_argv[argc + 2];
       new_argv[0] = (char *) _PATH_BSHELL;
       new_argv[1] = (char *) args->file;
       if (argc > 1)
-- 
2.17.1