The builtin assembler in clang is not intended for hand written assembly. Only that generated by clang. Disable this and use the default one
Setting `-target` flag explicitly is unnecessary. Whenever this needs to be explicitly passed through, the coompiler id should be checked. Changes to the musl build system makes the explicit `C_COMPILER` variable useless.
Having the basic compiler name in a variable lets us pass it around to any other user level project (e.g musllibc)
