Crosscompiler: cxxabi.h can't find cxxabi_tweaks.h

[tqh]

I'm not sure if I should report it, but at least the bug count goes up :P

I'm doing my fair bit of crosscompiling building Firefox (it runs, no gui though!) with gcc4 in Linux. When building a debug build it includes cxxabi.h (crosstools/include/c++/4.12/) and it includes bits/cxxabi_tweaks.h. That one isn't in the bits dir there, but it is in crosstools/include/c++/4.12/i586-pc-haiku/bits. As I was lazy I just copied it.

Feel free to reject if inappropriate.