Get rid of obsolete `{C,Cpp}Runtime_DigitalMars` special cases
Signed-off-by: Dennis <dkorpel@users.noreply.github.com>
Signed-off-by: Nicholas Wilson <thewilsonator@users.noreply.github.com>
Merged-on-behalf-of: Nicholas Wilson <thewilsonator@users.noreply.github.com>
Clang makes a distinction between clang and clang++. In particular, clang++ will give a warning when it is passed `.c` source files; and the extra output warning text means that dmd testsuite output checking fails. The warning can be silenced (-Wno-deprecated) but then other tests will fail because `#ifdef __cplusplus` will be true, leading to header file import issues.
