You need to get a version of libgcc.a that was built for cross-compilation. Some of the -lgcc routines that click's C++ code produces calls to in your native gcc's normal libgcc.a contains references to the native libc that just won't work to link with the oskit. When GCC is built as a cross-compiler, these problematic references are not compiled into libgcc.a (see `inhibit_libc' in gcc/libgcc2.c).