The Heirloom Development Tools provide yacc, lex, m4, make, and SCCS as portable derivatives of the utilities released by Sun as part of OpenSolaris. The OpenSolaris utilities were in turn derived from the original Unix versions, and are assumed be conforming implementations of the POSIX standard.
sccs2svn converts a SCCS repository into a Subversion repository. The script visits a directory tree with SCCS repositories. It then sorts the SCCS deltas by time and applies them to a Subversion repository. The script attempts to transform some SCCS keywords to Subversion keywords.