Previously, it was inconsistent in that some platforms/compilers
had this flag for the RelWithDebInfo configuration and some didn't.
This fixes issue #11366.
The commit "Split Intel compiler information files" moved some Linux
specific flags into the platform-independent Intel compiler info files.
This moves them back.
We set the variables to contain "-v", the verbose front-end output
option for Intel compilers. This enables detection of implicit link
libraries and directories for these compilers.