-arch i386 should be removed for Darwin

[krasylnikov]

Looks like we need to remove support for i386 architecture for newer OSX versions (ifeq ($(YQ2_OSTYPE), Darwin) case). There should be no "-arch i386" or "make" will fail with:

ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [release/game.dylib] Error 1
make: *** [3zb2] Error 2