Suppress header file information in AST; also, function prototypes vs definitions

I’m using clang 3.7 and am currently generating an AST for my test.c file with the following Windows 10 command line:
clang -Xclang -ast-dump -fsyntax-only test.c

  1. Is there any option that will suppress AST information from being generated for files that have been included in test.c via #include? I only want it for the code that is actually in the file.

  2. Due to the fairly simplistic tasks I am using the AST for at the moment I am merely parsing it myself rather than using libtooling or something more exotic. One thing I’m finding more complex than I’d like is that function prototypes and the declaration part of function definitions seem to be exactly the same in themsleves and I am forced to parse additional lines to differentiate them. Is there something I’m missing that would make differentiating them more straightforward?