Generally speaking when you are targeting that wide of a range of devices you are targeting a wide range of compilers. It requires some discipline but it's far from the hardest thing in the world assuming you are regularly building and testing for all platforms. I'd say that most major C++ applications or libraries compile in Clang, GCC and MSVC without issue and often build for less common targets as well (icc, nvcc for cuda support, etc.) Things definitely get harder when you move to weirder embedded platforms.