using directive in header file

I have a class that I need to convert to a template class. For this, I am moving the implementation from class.cpp to class-in.h that will then be included at the end of class.h.

The implementation has a few using ... directives as well as a gflag DEFINE_bool. I need to use these in the class-inl.h file but I am told that they shouldn't be placed in a header file. The class-inl.h is a header file but it will never be included as a regular header file.

Is there a way I can get rid of using/ gflag in the header file? Can I put the gflag, using statements in a class.cpp?