For your first problem: It should be obvious that warnings of the C compiler
makes not much sense for Nim generated code, as warnings are mostly for human
errors. Would you care for such warnings when Nim would generate assembly
directly? Even extremly ugly or verbose C code is fine as long as C compiler
can optimize it well. And it can, try gcc 10 with --gc:arc and -flto, gives
really small and still fast executables. (Looking for C compiler warnings may
be an option when there is indeed a bug somewhere...) Recently Nim devs have
explained well why C compiler warnings does not help, see
[https://forum.nim-lang.org/t/5785](https://forum.nim-lang.org/t/5785)
