Here is the source for Xlharc 1.2.  It has complete Atari ST and Unix versions.
See the CHANGES file for all of the changes I made to get this working on the
ST.

The Unix version is pretty much the same as the original 0.03 version and
doesn't have all of the same options of the ST version.  I don't intend to
support the Unix version although I will incorporate any fixes, that are sent
to me, into the source.  Read the READ.ME file for a list of the Unix LHarc
options.

TOS & Unix compiling:
        edit & configure Makefile
        make -f Makefile

NOTE:  The source code is heavily dependent on GCC 1.37 and it's libraries.
       (ST version).  As of 12/12/90, you cannot use version 1.37 of GAS to
       assemble lzhuf.c, IF you have specified -D__ASM__INSDEL__.  The
       resulting code will bomb.