-fno-strict-aliasing turned off when cross compiling

["Martin v. Löwis"]

> Does anyone have an idea why -fno-strict-aliasing is turned off when
> cross compiling?

Because detection of -fno-strict-aliasing is made through running
the compiler output (AC_TRY_RUN, see configure.in instead). For
cross-compilation, running the program isn't actually possible,
so a default must be specified. Since we can't know whether the
cross-compiler accepts -fno-strict-aliasing, we leave it out.

Regards,
Martin