bug#13479: Cross Compiling for ARM

[martin rudalics]

> Most/all calls to Elisp from C should protect themselves with calls to
> Ffboundp or similar, indeed.  Martin, could you take care of that?

I'm not sure.  If most/all calls should be protected we'd better provide
call_[1-4]_safe function for this purpose.  But I haven't the slightest
idea of what might happen when some of these functions don't get called.

martin