How to pass custom target CFLAGS for gcc with multilib?

[Miro Kropáček <miro.kropacek@xxxxxxxxx>]

Hello list,

I've got a pretty trivial problem. I'd like to build all gcc parts
with custom CFLAGS (say, for a specific sub-architecture) but not
affecting multilib CFLAGS (which are of course in conflict). Is there
some define like "CFLAGS_TARGET_WITHOUT_MULTILIB" ? Is this even
doable at all?

Thank you in advance for any suggestion.

Miro