(**) LibTool 1.4.2 had a bug related to cygwin's use of ".exe" extensions,
such that "make install" blew up at curl.exe. See this URL for details:
- http://mail.gnu.org/pipermail/libtool/2001-September/005549.html
+ https://lists.gnu.org/archive/html/libtool/2001-09/msg00101.html
The copy of ltmain.sh that is distributed with curl includes this patch.
As of curl 7.9.1, the official source compiles (under Cygwin) and tests