On Windows I have a number of versions of mingw(-64)/gcc installed. I
also have clang 3.4 through 3.9 installed as well as building the latest
clang 5.0 from source targeting gcc using gcc 6.3.
Other than the latest clang 5.0 I have built from source using gcc 6.3
is there any way, other than trial and error, to determine which backend
version of gcc a particular released version of clang will work with