* configure.ac: For Win32 environments, add a check whether the
compiler understands the -mno-cygwin option. If not, don't use
it but suggest using a different compiler.
git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk@930 81a1dc3b-b13d-400b-aceb-764788c761c2