bmake is a port of the BSD make tool (from NetBSD).

Version 3 was re-worked from scratch to better facilitate
importing newer make(1) versions from NetBSD.  The original code base
was NetBSD-1.0, so version 3 was built by doing a fresh import of the
NetBSD-1.0 usr.bin/make, adding the autoconf and other portability
patches to sync it with bmake v2, and then NetBSD's make 
of Feb 20, 2000 was imported and conflicts dealt with.
NetBSD's make was again imported on June 6 and December 15, 2000.

In 2003 bmake switched to a date based version (first was 20030714)
which generally represents the date it was last merged with NetBSD's
make.  Since then, NetBSD's make is imported within a week of any
interesting changes, so that bmake tracks it very closely.