arm: Compile LuaJIT without -DEXTERNAL_UNWIND on non-x86 platforms
arm: Compile LuaJIT without -DEXTERNAL_UNWIND on non-x86 platforms

External unwind code doesn't exists for non-x86 platforms.
Allow LuaJIT to be compiled somehow.

mejedi/tarantool,ocelot-inc/tarantool,rtsisyk/tarantool,mejedi/tarantool,mejedi/tarantool,rtsisyk/tarantool,rtsisyk/tarantool,ocelot-inc/tarantool,ocelot-inc/tarantool,mejedi/tarantool,rtsisyk/tarantool,ocelot-inc/tarantool