Virgin import of Flex v2.5.4
import vanilla flex version 2.5.35

Reviewed by:	cognet
Approved by:	cognet
Import flex 2.5.37.
Merge some important post-2.5.37 changes from upstream.

http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=c53fd2db8c78fef5afd284c3e64da51bc71cf6c3
http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=899b2163bbde1a70b3be8b91cbbabd8007341205
http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=7642bd98aebb62260df923f57b794138dab6f1e7
http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=11b7c6cea340c2fca9b49ec635a45bd34361afe9
http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=ec2fdb85e0bac6e8aeca405094506e4cf8bfc0b6
Clean up svn:keywords property.
Partially revert r250128.

http://flex.git.sourceforge.net/git/gitweb.cgi?p=flex/flex;a=commit;h=ec2fdb8

This patch is known to generate a broken scanner.

http://sourceforge.net/mailarchive/message.php?msg_id=29909582
Mention the switch to bmake by default.

Reviewed by:	obrien
Remove an extra semicolon from the DOT language output.

PR:		kern/178540
Submitted by:	Trond Endrestol
MFC after:	1 week
Disable keyword expansion.
Add flex 2.5.37 from flex.sourceforge.net to contrib.
Apply still relevant local changes.

r124183:	Work around a `label defined but not used' warning.
r179549:	De-register declarations.
r179657:	De-register declarations in non-dot-c files.
r181269:	Mark yy_fatal_error() as __dead2.
r228992:	Spelling fixes.
r240518:	Correct double "the the".
Reduce compiler warnings.
Do not use log10(3) to get rid of libm dependency.  It is really not useful.