We do this by making the mixins inherit the Compiler class only when
mypy is examining the code (using some clever inheritance shenanigans).
This caught a bunch of issues, and also lets us delete a ton of code.
intel compiler's defaults are different enough from MSVC and GNU
that it's necessary to set specific defaults for Intel compilers.
This corrects/improves behaviors initially addressed in b1c8f765fa
This puts appropriate default options across buildtype for Intel and
Intel-Cl compilers, for C, C++ and Fortran. Prior to this PR, the
behavior of Intel compilers vs. GNUlike was not the same, in
particular, debug traceback available by default for GNUlike compilers
was not present with Intel compilers.
Now that the linkers are split out of the compilers this enum is
only used to know what platform we're compiling for. Which is
what the MachineInfo class is for
Dylan Baker