[PATCH] Support cross-compiling for Arm on x86

[Rafael Espíndola]

> What problem are you actually trying to solve? Is it that the GCC installation is under a Major.Minor directory, and the headers are under a Major.Minor.Patch directory? Why on earth would that happen? It doesn't make any sense to me and so doesn't seem like something we should really support. I expect the GCC installation to have the same version number spelling as the libstdc++ installation, which seems like a sane place to be. Anything else and we're running the risk of version skew.

Commenting only on the problem, not the patch:

Something like that yes. On a vanilla 13.10 installation + arm cross
compiler we have /usr/lib/gcc-cross/arm-linux-gnueabihf/4.8 being a
symbolic link to 4.8.1, but in /usr/arm-linux-gnueabihf/include/c++/
there is only a 4.8.1.

The net result is that arm-linux-gnueabihf-g++-4.8 searches headers in

 /usr/arm-linux-gnueabihf/include/c++/4.8.1
 /usr/arm-linux-gnueabihf/include/c++/4.8.1/arm-linux-gnueabihf
 /usr/arm-linux-gnueabihf/include/c++/4.8.1/backward
 /usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/include
 /usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/include-fixed
 /usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/../../../../arm-linux-gnueabihf/include
 /usr/include

but libraries in

-L/usr/lib/gcc-cross/arm-linux-gnueabihf/4.8
-L/usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/../../../../arm-linux-gnueabihf/lib/../lib
-L/lib/../lib
-L/usr/lib/../lib
-L/usr/lib/gcc-cross/arm-linux-gnueabihf/4.8/../../../../arm-linux-gnueabihf/lib

Cheers,
Rafael