If we're C then use $CC and $CFLAGS. If we're C++ then use $CXX and $CXXFLAGS.
If we're C then use $CC and $CFLAGS. If we're C++ then use $CXX and $CXXFLAGS.

and if C++ with no $CXX/$CXXFLAGS, fallback to $CC/CFLAGS.

ryanmjacobs/c,ryanmjacobs/c,ryanmjacobs/c,ryanmjacobs/c