Fix cppcheck issues for incorrect language

Review Request #10067 — Created July 4, 2018 and submitted — Latest diff uploaded

Information

ReviewBot
release-1.0.x
ea10fbe...

Reviewers

cppcheck will fallback to C language if it checks a .h file.
A lot of C++ applications uses .h for C++ header. So cppcheck will
add issues for C++ only keywords like a "namespace".

This change adds another option to force cppcheck to use
given language.