The elusive "cc1" compilation error

[SamuelmsWong-zz]

Please see Jan's description of the error at issue #108 . From my own experience (on Linux), building the riscv cross-compiler multiple times from a clean pull has resulted in both successful builds and cc1 cannot be found compilation errors.

I was unsure whether this was a non-deterministic bug, but there is now a sensible idea for why it might be. Makefiles in the gcc libraries may run make with the -j flag to run independent builds in parallel. If dependencies are not fully specified in these makefiles, there is a possibility that two dependent builds are seen as independent and run in parallel. If build B is dependent on build A, it may be that B sometimes finishes before A and looks for files that do not yet exist.

Further investigation will be needed, but this hypothesis is here for future reference.