Makefile: Delay expansion of `$(ADAFLAGS)` This allows users of this library to extend `ADAFLAGS` from within their Makefile. The added flexibility makes this a very well spent dollar :-) Change-Id: I873d3eea48549e6945c4229b50c2318a3711bc4d Signed-off-by: Angel Pons <[email protected]> Reviewed-on: https://review.coreboot.org/c/libhwbase/+/43557 Tested-by: Nico Huber <[email protected]> Reviewed-by: Nico Huber <[email protected]>