Yes, designated initializers were added in ISO C99 and since Visual Studio 2013 they are also supported by MSVC.

But the code is neither ISO C99 nor C11. It uses a GNU C extension called “statement expressions”, which is not supported by MSVC.

Also, its preprocessor has quite a few problems. I think after removing statement exprs and running the code through a different PP, MSVC will compile it.

Of course, one could just simply use MinGW or Clang instead.

C99 compiler won't do, it also requires a GCC extension (statement expressions).