* misc/mntent_r.c (__hasmntopt): Check p[optlen] even when p == rest.

* misc/mntent_r.c (__hasmntopt): Check p[optlen] even when p == rest.

	Start searching for next comma at p rather than rest.
	* misc/Makefile (tests): Add tst-mntent2.
	* misc/tst-mntent2.c: New test.

	* misc/getusershell.c (initshells): Check for integer overflows.
	Make strings buffer one bigger as fgets always succeeds when second
	argument is 1.  Don't use calloc for shells array.  Disallow
	/ as shell.