That's definitely a huge disadvantage! But only supporting one compiler has the advantage that you're aren't limited to the lowest common denominator of compil

That's definitely a huge disadvantage! But only supporting one compiler has the advantage that you're aren't limited to the lowest common denominator of compiler features. You'll notice this especially with C++ codebases which try to support GCC, Clang, Intel and Visual C++. You'll need a lot of macros and workarounds for each compiler's quirks.