IMPORTANT NOTE: The build subsystem is not yet officially supported.
Please direct any questions on the topic to Arkady V.Belousov
(ark@mos.ru, arkady.belousov@gmail.com) for further detail. His
documentation on the build follows:

To build HIMEM and EMM386 executables, there present build subsystem
(which based on subsystem from FreeDOS kernel and customized similarly).

Build subsystem contains BUILD.BAT for compile (through MAKEFILE),
CLEAN.BAT to remove temporary files (listings, object files, etc),
CLOBBER.BAT, which removes also compiled executables, and support
files (*.CFG, *.MAK, other *.BAT files).

Also, there is a CONFIG.B file that specifies all the paths and name of
the (default) compiler, assembler and its options, etc. You must copy
it to CONFIG.BAT first, then edit to reflect real environment.

The reason for copying of CONFIG.B to CONFIG.BAT is that when new release
of the EMM386 package come out, you can extract it over previous sources,
and not have to worry about resetting up your configuration because your
CONFIG.BAT file will not get replaced!

Build subsystem supports assembling by NASM and TASM and compilation by
Turbo C 2.01, Turbo C++ 1.01, Borland C, MS VC and OpenWatcom - see
CONFIG.B for details. (Though, HIMEM/EMM386 sources are currently ready
only for TASM and Borland compilers. But NoMySo utility from
ftp://ftp.devoresoftware.com/downloads/nomyso/ allows to assemble some
TASM sources, including HIMEM/EMM386, by NASM.)

Optionally, HIMEM/EMM386 executables can be compressed using UPX. Simply
adjust CONFIG.BAT to enable it.

Syntax of BUILD.BAT: "BUILD [-r] [msc|wc|tc|tcpp] [86|186|386] [debug]"
(where "-r" clobbers all before compiling). These options allow on the
fly override paramaters from CONFIG.BAT without modifying it, and build
subsystem is enough smart to rebuild all if, for example, you select
different compiler, than previously.

Example of working CONFIG.BAT:

@echo off
set XASM=tasm /m/mx
set AFLAGS=/z/la/n
set COMPILER=BC
set TC_BASE=c:\devel\tc
set TCPP_BASE=c:\devel\tcpp
set BC_BASE=c:\devel\bc
set WATCOM=c:\devel\watcom15
if "%dos4g%" == "" set dos4g=quiet

Example of compilation:

command/c build >log    // compile and log all output to LOG file
build tc                // re-compile for COMPILER=TC

Resulting executables will be placed in SOURCE directory. Intermediate
(non-packed) execuatbles are reside in directory with batch files - they
may be useful for debugging.