Adding Flags to Compilation of rtld-libc.a

[Florian Weimer]

* Vance Raiti via Libc-help:

> It's not clear to me where these special flags are set (perhaps it's
> CFLAGS-.os?), so if I wanted to compile the members of rtld-libc.a with
> -UUKL_BP, where could I add it?

You can use #if IS_IN (rtld), presumably in <sysdep.h>, where the system
call interface is defined.

Thanks,
Florian