Aubit 4GL SVN-Code

lex_cs was copied into the tree but never added to SVN, so it - and the
retargeting in r13050 - existed only in a working copy. This adds the 16
source files the plug-in builds from, 432K in total.

Deliberately NOT added: the directory also holds about 35M of backup
copies (latest/, 250210/, CM/, old1/, backup_221009/), seven copies of
the same 1.7M tarball, and .exe/.dll/.mdb binaries including an Informix
DLL. Those are ignored rather than versioned; they are still on disk if
any of them turn out to matter.

The plug-in is still not built by the top-level make - it has to be
built by hand in lib/liblex/lex_cs. Wiring it in is a separate decision,
since it would make every build depend on it.