Don't assert() on mixed of designated and non-designated initializers.
Update the second unit test to test mixed designated and non-designated initializers
Add an assertion if particular indices in an array/struct are duplicates.

Fix struct/array index lookup if the previous entry used a designated
initializer, but this particular entry didn't. In that case, our index
is the previous member's index + 1, but we used to use the counter as
index, which is wrong.

Also fix the unit test, which contained code triggering both problems,
which ended up going in an infinite loop.
Add binaries link.
Automatically enable microsoft compatibility if converting for cl.exe

This is required for handling MSVC headers, with a libclang not
built with MSVC. (For libclang built with MSVC, these options are
enabled by default.)

This allows using the same c99conv/wrap binaries for both MSVC
and gcc.