Now as long as you have a C compiler available in the project, it will
be used to compile assembly even if the target contains a C++ compiler
and even if the target contains only assembly and C++ sources.
Earlier, the order in which sources appeared in a target would decide
which compiler would be used.
However, if the project only provides a C++ compiler, that will be
used for compiling assembly sources.
If this breaks your use-case, please tell us.
Includes a test that ensures that all of the above is adhered to.