* MODULES.html.sh (Extra functions based on ANSI C 89):
Add secure_getenv.
* doc/glibc-functions/secure_getenv.texi: New file.
* doc/gnulib.texi: Include it.
* lib/secure_getenv.c, m4/secure_getenv.m4, modules/secure_getenv:
New files.
* lib/stdlib.in.h (secure_getenv): New decl.
* m4/stdlib_h.m4 (gl_STDLIB_H, gl_STDLIB_H_DEFAULTS):
* modules/stdlib (stdlib.h):
Add secure_getenv checks.
