LWG Issue 2141: common type

[Jonathan Sauer]

Hello,

> Also, a drive by fix on the tests for is_trivially_copyable. Clang recently fixed a bug in the intrinsic that libc++ uses for this type_trait, and this exposed an error in the test suite.

Not sure about the policy for renaming misnamed files, but if it's fine to do so I think
"is_trivialially_copyable.pass.cpp" should be corrected to "is_trivially_copyable.pass.cpp".


Jonathan