[MinGW-dvlpr] flex 2.5.33 under MSYS

[Julien L. <ju...@fa...>]

x-post: mingw-dvlpr & flex-devel

I recently was trying to compile flex under MSYS, and stumbled upon 
MinGW/MSYS mailing-list documentation on the compiling problems of it 
and of libregex.
For archive purposes, I'm posting the solution I had to use to correctly 
compile flex for MSYS; as the current archives didn't post a full 
solution. This might also be of use for the next MSYS release.

Among the problems of the compiling flex, there's a 'regex.h' problem 
(header not found) and then I stumbled upon another problem where all 40 
test cases fail (internal regcomp error).

Here's my solution:
- download libregex (currently 0.12, on ftp.gnu.org/old-gnu/regex)
- extract, configure and make only object (make CFLAGS="-O2" regex.o) as 
we (I?) don't care about tex.
- make a library out of it (ar -crs libregex.a regex.o)
- copy them to correct locations (cp libregex.a /usr/lib/ && cp regex.h 
/usr/include/)

- extract flex, configure and make (make should succeed, but flex.exe 
should have regcomp errors if you try './flex.exe')
- remove flex.exe, and use a modified link command:
rm flex.exe
gcc -o flex.exe ccl.o dfa.o ecs.o gen.o main.o misc.o nfa.o parse.o 
scan.o skel.o sym.o tblcmp.o yylex.o options.o scanopt.o buf.o tables.o 
tables_shared.o filter.o -lregex regex.o

If you now run the test case, you should have 4 errors, most are because 
they are C++ errors and inclusion of non existing _G_config.h; and one 
of them is just solved by running test case with correct CFLAGS and LDFLAGS.

Cheers,
Julien