Hei hei, 

currently I'm working on building OpenNI [1] with ptxdist. I take the
source from GitHub [2] and try writing an appropriate rules/openni.make
– however this is not as easy as it seems. :(

OpenNI does not use standard tools like autotools or cmake for
uncomplicated cross compiling but some hand written Makefile. They have
a very short section in their README how to cross compile:
https://github.com/OpenNI/OpenNI/blob/master/README

For doing this without ptxdist I create a folder ~/build/sysroot and
tried cross compiling. Doing it like in the README this results in an
error stating 'unistd.h' is not found. If I copy the content of
/opt/OSELAS.Toolchain-2011.03.0/arm-v5te-linux-gnueabi/gcc-4.5.2-glibc-2.13-binutils-2.21-kernel-2.6.36-sanitized/sysroot-arm-v5te-linux-gnueabi
to ~/build/sysroot/ first, compiling succeeds (after manually cross
compiling libusb and installing it to ~/build/sysroot).

In ptxdist compiling fails with the same error, the unistd.h is not
found. There's none in my BSP in platform-at91.../sysroot-target – I
guess all the other packages are able to find these libc include files
somewhere else, maybe in the same subfolder of the toolchain. I assume I
should not copy these files to sysroot-target and I should also not let
the openni Makefile install stuff in my toolchain.

The Makefile of OpenNI can be found at [3] but I'll also attach how far
I got with my rule files.

I tried finding out how autotools or cmake generate their Makefiles or
what ptxdist calls in the compile stage so other packages find their
stuff, but this is horribly complex. :-/

Maybe someone has a hint how to pass some parameter or patch the
Makefile? I guess it lacks on some understanding of cross-compiling
here. O:-)
Alex

[1] http://www.openni.org/
[2] https://github.com/OpenNI/OpenNI
[3]
https://github.com/OpenNI/OpenNI/blob/master/Platform/Linux/Build/Makefile

-- 
»With the first link, the chain is forged. The first speech censured,
the first thought forbidden, the first freedom denied, chains us all
irrevocably.« (Jean-Luc Picard, quoting Judge Aaron Satie)
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