[Bug d/103528] [12 regression] d21 doesn't build on Solaris

[ibuclaw at gdcproject dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103528

--- Comment #7 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
Created attachment 52018
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52018&action=edit
configure check compiler driver understands D

How does this patch look?

Because the module name is not "object", it both tests that:
1) The CC driver knows about the D language
2) Compiler proper implicitly tries to import object.d, which would fail if
libphobos was disabled for reasons.