To build SyncTERM, you *will need* the following bits from the Synchronet CVS
tree:

src/build/*
src/conio/*
src/sbbs3/telnet.c
src/sbbs3/telnet.h
src/sbbs3/zmodem.c
src/sbbs3/zmodem.h
src/sbbs3/xmodem.h
src/sbbs3/sexyz.h
src/hash/*
src/encode/*
src/syncterm/*
src/uifc/*
src/xpdev/*
src/comio/*
3rdp/build/Common.gmake
3rdp/build/Common.make
3rdp/build/GNUmakefile
3rdp/build/targets.mk
3rdp/dist/cryptlib.zip
3rdp/dist/*.patch

The directory structure under src *must* be kept intact.  Once you have all
this in place, a simple "make" should build everything you need.  If you're
using *nix you must use GNU Make... under some systems (Such a most BSDs) this
is optional and installed as "gmake" rather than "make".

When building from the source archive, need to set SRC_ROOT to the extracted
path name to locate the bundled 3rd party sources like so:
make SRC_ROOT=/path/to/syncterm-20120226
This can be done using backticks as well:
make SRC_ROOT=`cd .. ; pwd`
or:
make SRC_ROOT=`realpath ..`

Refer to src/build/Common.gmake or src/build/Common.bmake for details of some
of the make options the build system supports.

Release builds for Mac OS X use the following command line:
make RELEASE=1 USE_SDL_AUDIO=1 PREFIX=/usr

The package is generated and copied do a disk image which is then converted
with the following command:
hdiutil convert ~/Desktop/SyncTERM.dmg -format UDRO -o /Volumes/Synchronet/sbbs/web/root/syncterm.bbsdev.net/SyncTERM.dmg -ov

Release builds for Win32 using MinGW32 use the following command line:
gmake CC=mingw32-gcc VERBOSE=please AR=mingw32-ar AS=mingw32-as RANLIB=mingw32-ranlib RELEASE=1 CXX=mingw32-g++ WINDRES=mingw32-windres

32-bit Release builds for Win32 using MinGW-w64 use the following command line:
gmake AR=i686-w64-mingw32-ar AS=i686-w64-mingw32-as CC=i686-w64-mingw32-gcc CXX=i686-w64-mingw32-g++ RANLIB=i686-w64-mingw32-ranlib WINDRES=i686-w64-mingw32-windres RELEASE=1 VERBOSE=1

32-bit CMake builds for Win32 using MinGW-w64 on my system uses:
cmake -DWITHOUT_ALSA=ON -DWITHOUT_PULSEAUDIO=ON -DCMAKE_TOOLCHAIN_FILE=/synchronet/src/sbbs/src/syncterm/FBSD-mingw64.cmake ..
cmake --build . -j4
This does not rebuild cryptlib, so is suspect.

64-bit Release builds for Win32 using MinGW-w64 use the following command line:
gmake AR=x86_64-w64-mingw32-ar AS=x86_64-w64-mingw32-as CC=x86_64-w64-mingw32-gcc CXX=x86_64-w64-mingw32-g++ RANLIB=x86_64-w64-mingw32-ranlib WINDRES=x86_64-w64-mingw32-windres RELEASE=1 VERBOSE=1

Release builds for Emscripten use the following command line:
gmake CC=emcc VERBOSE=please AR=emar RANLIB=emranlib RELEASE=1 CXX=emc++ os=emscripten

Release builds of jsdoor (not related at all)
gmake jsdoor NO_LD_RUN_PATH=dumbass CC=mingw32-gcc VERBOSE=please AR=mingw32-ar AS=mingw32-as RANLIB=mingw32-ranlib RELEASE=1 CXX=mingw32-g++ WINDRES=mingw32-windres JSLIBDIR=../../3rdp/win32.release/mozjs/bin/ JSINCLUDE=../../3rdp/win32.release/mozjs/include/ JSLIB=mozjs

Building a dpkg for a Debian-like OS
gmake RELEASE=1 PREFIX=/usr dpkg