Allow the CTYPE macros to be disabled, forcing procedure calls to be used

Allow the CTYPE macros to be disabled, forcing procedure calls to be used
instead.

Disable the CTYPE macros in libskey, libutil, and libcrypt.  This allows
pre-1.3 programs linked against libc.so.3 to use the PAM modules in HEAD.
these modules indirectly reference libskey, libutil, and libcrypt, which
then fail to dynamically link against libc.so.3 due to references to
ctype globals that do not exist in libc.so.3.

This is a hack, I know, but we have to make upgrades as compatible as
possible with older programs.