delete whitespaces that end up in output files

Update flex from ancient 2.5.4 to the recent 2.5.39.
This work was all done by Serguey Parkhomovsky. Thanks.
Some changes from upstream:
* Removed autotools cruft/localization/texinfo manual/etc
* Kept the old manpage, as the new manpage is content-free
* Used safe string handling functions and fixed several compiler warnings
* pledge(2). Flex 2.5.39 now forks/execs its filter chains and needs proc
exec in addition to what was previously pledged
* Removed register keyword from all variable declarations
* renamed parse.c, parse.h, scan.c, skel.c with init prefix so compiling
flex outside of obj by accident wouldn't clobber the bootstrap files
* Minor fixes (spelling, accessing buf[strlen(buf) - 1] for zero-length
strings in initscan.c/scan.l, etc) that were already in our tree

This is a huge change, so it's going in the tree code bomb style.
I'm not excited about the growth in complexity (like now running m4
to _post_ process lexers) but hopefully this will be a one time update
and we will now take "ownership" of the code.

Update flex from ancient 2.5.4 to the recent 2.5.39.
This work was all done by Serguey Parkhomovsky. Thanks.
Some changes from upstream:
* Removed autotools cruft/localization/texinfo manual/etc
* Kept the old manpage, as the new manpage is content-free
* Used safe string handling functions and fixed several compiler warnings
* pledge(2). Flex 2.5.39 now forks/execs its filter chains and needs proc
exec in addition to what was previously pledged
* Removed register keyword from all variable declarations
* renamed parse.c, parse.h, scan.c, skel.c with init prefix so compiling
flex outside of obj by accident wouldn't clobber the bootstrap files
* Minor fixes (spelling, accessing buf[strlen(buf) - 1] for zero-length
strings in initscan.c/scan.l, etc) that were already in our tree

This is a huge change, so it's going in the tree code bomb style.
I'm not excited about the growth in complexity (like now running m4
to _post_ process lexers) but hopefully this will be a one time update
and we will now take "ownership" of the code.