Ok... here's how I compiled Tierra with DJGPP...

What I used:

Tierra 4.3 Distribution ( tierra43_tar.gz ) unzipped with the directory
structure preserved.

DJGPP v2.01 (I used the complete installation but you should get away with
just the basic package described in the FAQ:s included with DJGPP v2.01, as
Tierra doesn't use any C++ or ObjC).

DJGPP port of binutils (I used bnu281b.zip but the previous version should
work too) (the binutils contain the cp and rm commands needed by both the
.bat files included with the distribution and the makefile.)

DJGPP port of GNU Make 3.75. If you just want to compile it with the .bat
files included with the distribution you don't really need this, but it's
more convenient.

And, I used the makefile attached to this mail. The makefiles in the
distribution cannot compile Tierra with DJGPP. Just put the makefile in the
Tierra source directory, and type:

        make -f Makefile-DJGPP all

This will compile both tierra.exe and arg.exe (the genome
assembler/disassembler) and prepare the genomes in the gb directories.

If you don't want the .o files afterwards or if you want to recompile it:

        make -f Makefile-DJGPP clean

If you want, you can edit the makefile if you want to include or exclude
different optimizations (it's quite optimized in the makefile, and
unexpectable things MIGHT happen) or if you want to turn on debugging of
the executable (-g). Also, the makefile removes the symbol tables and
relocation information (the -s switch to gcc), which makes the executable
smaller.

Now you should be up and running, by just typing 'tierra si0'. And... by
all means, read the tierra.doc thoroughly ;-)