Unsolved Qt Creator: g++ for both c and cpp files

[anshah]

I am using Qt Creator (Qt 5.9) on an integrated project which contains non-Qt files but on top of that the files are C and C++. Qt Creator has an option in the build tools for g++ for the *.cpp files and gcc for the *.c files.

I want to force the *.c files to compile using g++ instead of gcc but I can't figure out how to do that. Any ideas? Any thing I should add to the .pro file?