Add further documentation for build environments

[jatkinson1000]

Following discussion #162 we should consider updating the documentation to not only suggest using the 'same Fortran compiler', but instead note that one really needs to compile with the same environment (particularly gcc, even when using intel compilers due to the GLIBC dependency).

[ElliottKasoar]

Not that I would recommend it, but I think I had some successful installations with mixed Fortran and C/C++ compilers. Definitely clearer warnings of potential issues and the sort of errors/how to resolve them would be useful, as I think it's one of the things that trips people up the most.