RFA: Save LDFLAGS and CPPFLAGS at the top level

[Paolo Bonzini]

Daniel Jacobowitz wrote:
> This patch should make all of {CPP,LD}FLAGS{,_FOR_TARGET,_FOR_BUILD}
> work from the top level.  The GDB simulator directories don't always
> listen to them (partially tested patch posted), and I'm sure there are
> other omissions, but this fixes what I could find by inspection.
> 
> Tested by building an arm-none-eabi simulator for both current Linux
> host and cross-built Windows host, with CPPFLAGS/LDFLAGS set before
> running configure, and checking every command in the log.  Without
> this patch those CPPFLAGS and LDFLAGS are not used, with it they are.
> 
> OK?

Yes, thanks.

Paolo