include/llvm-c: Whitespace.
llvm-c-test: Make them C89-compliant.
llvm-c/lto.h: Avoid use of bool.
llvm-c/Target.h: Tweak "inline" for msvc to use __inline instead.

FIXME: I don't think it'd be smart.
llvm/tools/llvm-c-test should be built also on msvc.
Add llvm-c-test to check-llvm.