nnesse/minwin-gcc-5-2: A patched gcc 5.2 enabling a new 'minwin' target that does not link to the Microsoft C library.

Niels Nesse eb72d50f44 Import gcc 5.2.0 from tarball		9 lat temu
..
ffitestcxx.h	eb72d50f44 Import gcc 5.2.0 from tarball	9 lat temu
special.exp	eb72d50f44 Import gcc 5.2.0 from tarball	9 lat temu
unwindtest.cc	eb72d50f44 Import gcc 5.2.0 from tarball	9 lat temu
unwindtest_ffi_call.cc	eb72d50f44 Import gcc 5.2.0 from tarball	9 lat temu