[BuildTools] BuildTools version incompatibilities (cygwin, -mno-cygwin)

[Lou Hafer]

Folks,

	There have been a couple of tickets posted (Osi, CoinUtils, BuildTools)
complaining about a compile problem on cygwin (_isnan not declared).  I can't
duplicate this error (I suspect it's fixed in the current BuildTools), but the
current Osi stable (0.95) and point release are incorporating externals with
incompatible versions of coin.m4.  CoinUtils has upgraded to a version with the
--enable-doscompile flag, hence -mno-cygwin is absent by default.  But the clp
and dylp point releases are still built with an early BuildTools that does not
have --enable-doscompile and hence uses -mno-cygwin by default.

	Andreas, do you think we're ready to try the leap to autoconf 2.61?
We'll need that to avoid known problems with dylp configuration and the cl
compiler. If not, I'll back out to 2.59 locally and generate a new DyLP point
release that's compatible with current CoinUtils.

	Short-term workaround is to use --enable-doscompile, so that CoinUtils
builds with -mno-cygwin.

							Lou