This provides a more straightforward way to place the compiler in a "strict conformance" mode. This could essentially be achieved by setting several pragma options, but having a single setting is simpler. "Compatibility modes" for older standards can also be selected, although these actually continue to enable most C17 features (since they are unlikely to cause compatibility problems for older code).
Specifically, the following will now be tokenized as keywords:
_Alignas
_Alignof
_Atomic
_Bool
_Complex
_Generic
_Imaginary
_Noreturn
_Static_assert
_Thread_local
restrict
('inline' was also added as a standard keyword in C99, but ORCA/C already treated it as such.)
The parser currently has no support for any of these keywords, so for now errors will still be generated if they are used, but this is a first step toward adding support for them.