module imports from -fauto-module-import to -fmodules. The new name
will eventually be used to enable modules, and the #include/#import
mapping is a crucial part of the feature.
llvm-svn: 147447
features needed for a particular module to be available. This allows
mixed-language modules, where certain headers only work under some
language variants (e.g., in C++, std.tuple might only be available in
C++11 mode).
llvm-svn: 147387