option is given to the compiler. It's silly to have to specify it twice
on a command line (e.g. -mcpu=ev56 -Wa,-mev56), especially considering
that if you don't, and the compiler emits e.g. a BWX instruction, the
assembler will treat it as a macro, open-coding an equivalent, which can
have some serious unwanted side-effects in some situations.
Also, don't treat e.g. 21164 and ev5 as equivalent; the assembler treats
them differently: 21164 enables PALcode-only instructions, while ev5
does not.