htdbm: Enable crypt support on platforms with crypt() but not

<crypt.h>, such as z/OS.

We assume that the ancient code in htpasswd has it right --
all but Windows, TPF, and NetWare have crypt().

Submitted by: David Jones <oscaremma gmail.com>
Reviewed by: wrowe, trawick



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@526892 13f79535-47bb-0310-9956-ffa450edef68