Temporary fixes for sizes and mangled names.

1) clang segfaults on trying to mangle a global variable name who's type is
   a dependent sized array type.
2) Sizes of auto types are not deducible.
3) Do not look at source files for exported abi.

Test: header-abi-dumper -o example1.dump tests/input/example1.cpp -I tests --
      -x c++ -std=c++11 -I . -I ~/android/aosp/external/clang/lib/Headers

Change-Id: I9fcab6c8bf82df2aace0161b14f397f34ef0d51e