On aarch64-linux-gnu, unwind tables aren't emitted by default (contrary
to x86_64-linux-gnu), so we must pass the flag (or -funwind-tables)
to the compiler to make it generate them.

Previously wine just added the flag to the linker options.
Signed-off-by: Martin Storsjo <martin@martin.st>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>