My tiny (~54k on osx/x86_64; smaller on 32 bit machines) & ancient
(first written sometime in 1979 (in USCD pascal; I converted it to C
 sometime in the early 1980s)) almost-vi-clone.

I think it implements about 95% of visual mode;  I still use it on
most of my machines and only notice things lacking in exec mode
(I don't implement :g and :v) and when displaying long lines (standard
vi wraps, I -- following the lead of the USCD pascal editor -- truncate.)

Over its life it's been built on

* USCD pascal (in Pascal, then in p2; those sources may no longer exist
  because 8" floppies were expensive and I didn't do version control
  because they were tiny)
* TOS on the Atari ST
* MS-DOS
* Flexos
* iRMX
* OS/2
* Linux (the first version to make it into SCCS, in 1993, after 13 or
  14 years of use, porting, and development)
* FreeBSD
* NetBSD
* Macosx
* Windows 10

And it's currently (version 4) being built on Unixes (osx,*bsd,Linux),
Windows 10, and OS/2 v4 (both windows 10 & OS/2 are using their
respective console ANSI emulation, both of which have issues.)


The configuration options are

*  --use-termcap; link with termcap instead of curses, if at all possible.
*  --partial-install; don't install the lv, lv(1) name links.
*  --size=NNN; use an NNN-byte editor buffer (this is the maximum sized
   file that can be edited without truncation.
*  --stdio; use stdio for buffered i/o whenever practical
*  --logging; write copious logs to levee.log (in the startup directory)
*  --tputs; write control strings using the pacing functions in termcap
*  --noglob; don't use the system glob() function to expand wildcards
*  --ucsd; enable reading ucsd pascal .text files (via the -p option)
*  --dos; build for ms-dos
*  --tos; build for TOS
*  --rmx; build for iRMX
*  --flexos; build for flexOS
*  --win10; build for Windows (only tested on Windows 10)
*  --prefix; root of where to install things (defaults to /usr/local)
*  --execdir; where to install binaries ($prefix/bin)
*  --mandir; where to install the manpages ($prefix/man or $prefix/share/man)