Log message:
Add RMD160 checksum.

Log message:
Remove USE_BUILDLINK3 and NO_BUILDLINK; these are no longer used.

Log message:
Rename some variables to be more dlcompat-specific, and remove a
redundant conditional.

Log message:
dlcompat is considered built-in only if both /usr/lib/libdl.* and
/usr/include/dlfcn.h exist.  Also, correct the setting of
USE_BUILTIN.dlcompat in the loop.

Log message:
Standardize how we search for libraries in builtin.mk files.  We define
_BLNK_LIB_FOUND.<lib> to "yes" or "no" depending on \ 
whether -l<lib> is
found in the base system.

Log message:
dlopen.buildlink3.mk will automatically include dlcompat/buildlink3.mk
only on Darwin, so remove OPSYS check in dlcompat/buildlink3.mk and
make packages include dlopen.buildlink3.mk instead.

Log message:
dlcompat was added to OS X "Panther". Add a builtin.mk to detect
its presence. Bump BUILDLINK_DEPENDS to the latest version.

Evaluate the contents of buildlink3.mk only if we're on Darwin,
which lets us simply .include "../../devel/dlcompat/buildlink3.mk"
anywhere we might need it without affecting other platforms.

Log message:
no longer used.

Log message:
use buildlink3.

Log message:
Reorder location and setting of BUILDLINK_PACKAGES to match template
buildlink3.mk file in revision 1.101 of bsd.buildlink3.mk.