Add support to build MinGW tools using Cygwin. This is a Canadian cross
build.
Do not expand the directives when parsing a configuration file. Hold
in the package object the text as read from the configuration file. Still
parse the logic but leave the macros. This allows a configuration to be
varied when the build happens. The Canadian cross uses this to build a
build compiler used to build a Cxc runtime.
Add Cxc support to the build module. In the defaults add rm and rmfile
macros, add Cxc paths and pre-build script code.
In the setbuilder check for a Cxc build and if so and the package
allow Cxc build the build host version then the host target
version.
Add cygiwn support to the defaults processing and to the Windows module.
Autoconf hard codes paths into itself. This change is a first
pass at allowing a clean environment to let automake build. The
ability to 'make install DESTDIR=xxx' autoconf then use it to
build automake needs a clean environment. The purpose is to
allow a prefix that needs root without building and packaging
when root.