Log Message:
Create a pam.buildlink3.mk file that is used by PAM-using packages.
It includes the correct buildlink3.mk file from either Linux-PAM
(security/PAM) or OpenPAM (security/openpam) and eventually will
support solaris-pam.  pam.buildlink3.mk will:

	* set PAMBASE to the base directory of the PAM files;
	* set PAM_TYPE to the PAM implementation used.

There are two variables that can be used to tweak the selection of
the PAM implementation:

PAM_DEFAULT is a user-settable variable whose value is the default
	PAM implementation to use.

PAM_ACCEPTED is a package-settable list of PAM implementations
	that may be used by the package.

Modify most packages that include PAM/buildlink3.mk to include
pam.buildlink3.mk instead.