gccutils: get pretty-printing working again

[jackrosenthal]

• Add new function gcc.is_cplusplus to determine if we are compiling C++

• Use gcc.is_cplusplus in gccutils to not iterate over fullname when we are not using C++ (resolves davidmalcolm#72)

• Allow accessing gcc.Type.sizeof to raise a TypeError while pretty-printing to be silently ignored and not added to attributes

• Use pp_newline_and_flush instead of pp_newline in PyGccPrettyPrinter_as_string when we are using GCC 5.3 or later (as this provides the historic functionality relied upon)

[jackrosenthal]

ping!

[jackrosenthal]

Hi, is this project still being mantained? I sent this pull request over two years ago and haven't heard back. Can we merge?