[Issue 24852] LDC fails when compile foreach for the target avr.

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24852

--- Comment #3 from cbleser <cr at tagion.org> ---
I just noted that the size_t for the AVR 8-bit processor is uint.
But the process can only address 16 bits so it should properly be ushort and
ptrdiff_t should be a short.

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