Earlier quoted context omitted.
Basically I am not able to compile my particular codebase in clang or gcc too easily since it's an embedded system. But many other IDEs have no problem inferring autocompletion without requiring compilation. YouCompleteMe itself was a bit of an issue as I have to develop in Windows and it's not quite as well supported.
You should use a different completion plugin then. YCM is the only one that needs to be compiled. If you use regular vim, check out neocomplete, and if you use neovim, well, you should know about deoplete (it's kickass). Both of these pretty much work out of the box; they have accompanying clang sources (vim-clang or deoplete-clang) that feed the suggestions to neocomplete/deoplete. Frankly, I would use neovim + deop…
[0] https://github.com/zchee/deoplete-clang [1] https://github.com/zchee/deoplete-clang/issues/57