This test is currently failing:
----
    byte* p;

    version(X86)
        assert(p.sizeof == 4);
    else version(X86_64)
        assert(p.sizeof == 8);
    else
        assert(false, "unknown platform");
----

we could of course just add a
----
    else version(ARM)
        assert(p.sizeof == 4);
----

but I wonder whether this should use D_LP64 instead? With armv8/AArch64 arm will support 64bit pointers. The question then is whether we introduce a new version for 64 bit version(ARM64), or whether version(ARM) could be 32 or 64 bit and we should additionally use version(D_LP64)?