[TUHS] Doug McIlroy's C++ regular expression library (mostly) revived

[Arnold Robbins <arnold@skeeve.com>]

Hi All.

I have (mostly) revived Doug McIlroy's C++ regular expression parsing
library.  I gratefully acknowledge and thank him for allowing me to
publish the code and for his help in finding all the bits and pieces.

It's available at https://github.com/arnoldrobbins/mcilroy-regex .
The main things I've done are to gather all the bits and pieces, rename files
to have a .cpp extension, and get everything to compile using current g++
and standard make.

I'm at the point where I could use some help. The various tests
do not all run successfully. 

1. make retest - a number of tests fail
2. ./tesgrep.sh - a number of tests fail
3. ./testsed.sh - tests fail with core dumps

Looking briefly, some of the code in sed plays C games, casting various
things arouond to pointers of different types and dereferencing them;
these things tend to cause trouble in C++.

I'm hopeful that more eyes on this code will help it come back to life
more quickly.  Any and all help will be appreciated.

Thanks,

Arnold

P.S. Let's not start a flame war about C vs. C++ etc. etc.  If you can
help, please just dive in. Otherwise, just go, "wow, neat work" and
move on to something else. :-) Thanks.