Support testing of C-language test files under tests/c
Preparation for tests for issue #123.

git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@529 812d1f90-f944-d88a-411a-122bdc93e1ea
Fix issue #123: improve handling of structs
Elaborated types only imply forward declaration in C++
(Clang throws a warning for elaborated structs in C code),
so require a forward declaration for elaborated struct types
when compiling C code.

git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@530 812d1f90-f944-d88a-411a-122bdc93e1ea
Add full stop at the end of new comment.


git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@531 812d1f90-f944-d88a-411a-122bdc93e1ea