AIX Cross compile on Mac OS X

[Kai Ruottu]

Brian Dessent wrote:
> By the time you have a working cross-binutils and cross-gcc getting the
> target libraries cross compiled should be pretty simple, assuming that
> you've copied over the system headers into $prefix/$target/include and
> startup objects into $prefix/$target/lib.
>   
 Please define "system headers"!  The obvious assumption is that the 
"system headers"
will go into the '$prefix/$target/sys-include' meanwhile the "standard 
headers" (those
usually in '/usr/include' natively) will go  into the 
'$prefix/$target/include'.  A cross-GCC
has always places for both types of headers although only some few 
systems have any
"system headers" in their native GCCs...  Whether AIX has these is 
unclear, BeOS and
Mach at least once had the SYSTEM_INCLUDE_DIR defined for them....

The very well-known bug in the GCC sources has been that during the GCC 
build the
place aimed for the "system headers", the 'sys-include',  is where the 
"standard headers"
are expected to be for "fixinc" and existence checks!  The "GCC 
Internals" manual says
in:

     http://gcc.gnu.org/onlinedocs/gccint/Header-Dirs.html#Header-Dirs

about these things totally differently :-(   It is really surprising 
that this kind of clash between
the GCC documentation and what the GCC build really does, can have been 
"maintained"
years and years....

 The work-arounds for this bug have been to use the '--with-headers=' 
which copies the
pointed headers into 'sys-include' (people are assumed to be not capable 
to use even 'cp'?),
or  make a 'sys-include' symlink  to point to the 'include' where the 
target standard headers
are preinstalled (some people can even be capable to make symlinks)....

 Generally if  the 'fixinc' succeeds in a native build, it should also 
succeed in cross build! If
only those standard headers are seen also as "system headers" (whatever 
they then are)....
The problems have been with the GCC targets which don't have "native" 
GCCs for them
at all,  trying to "fix the already fixed" C library headers made for 
only GCC, like those
in 'newlib', has many times been a fiasco, the fixing for instance 
removing all spaces from
some originally working headers....  So all kind of theories about the 
"sys-include bug" being
a way for the builder to choose whether the target headers should or 
shouldn't be "fixed"
for GCC,  have floated around this so weird thing in the cross-GCC build....