``Embedded``
  Compile with ``-Z7`` or equivalent flag(s) to produce object files
  with full symbolic debugging information.
``ProgramDatabase``
  Compile with ``-Zi`` or equivalent flag(s) to produce a program
  database that contains all the symbolic debugging information.
``EditAndContinue``
  Compile with ``-ZI`` or equivalent flag(s) to produce a program
  database that supports the Edit and Continue feature.

The value is ignored on non-MSVC compilers but an unsupported value will
be rejected as an error when using a compiler targeting the MSVC ABI.

The value may also be the empty string (``""``) in which case no debug
information format flag will be added explicitly by CMake.
