msvc: handle filename extensions for incdetect based on the compiler language

It is possible, albeit possibly inadvisable, for the exact combination
of MSVC and "$CXX has C++ specific flags in it" to occur. When this
happens, and cl.exe is given a filename ending in .c, it complains that
you cannot compile a .c file with that option.

Instead, pick the first filename matching that language and use that as
the temporary filename. This more or less matches what we do in
compiler-time checks. And it's the proper thing to do, rather than
assume that cl.exe, when detected as the current C++ compiler, can
*also* compile C because it's *also* a C compiler.

Fixes #11257

0 files changed, 0 insertions, 0 deletions