[more canadian cross errors] TOPLEVEL_INCLUDES

[Daniel Jacobowitz <dmj+ at andrew dot cmu dot edu>]

TOPLEVEL_INCLUDES is explicitly used only during a Canadian cross.  I don't
see why it needs to be used at all, or how it could be right for that.

Consider: we are building a Canadian cross.  It is something which can not
possibly run on the build system.  That's the point.  --includedir gets
hardcoded into the compiler as LOCAL_INCLUDE_DIR.  Obviously, --includedir
is referring to something which should exist when the built compiler is run. 
Which it won't be, on the build machine.

So I build my Canadian cross, TOPLEVEL_INCLUDES is /usr/include because I
don't need a custom includedir on the system the compiler is meant to run
on, and /usr/include brings in header files with x86 assembly.  Not good
when building a MIPS target.

What does the inclusion of -I$(includedir) accomplish?  Is it generally, or
ever, necessary?

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer