Subsidiary fix for issue 6210.

[quickfur]

Add builtin typeinfo for const(char)[] so that it will use the same hash function as char[] and string.

Subsidiary pull for dlang/dmd#2479

[quickfur]

Hmph. This fix requires dmd to be patched with dlang/dmd#2479, but obviously the autotester isn't using the patched compiler. How to get around this? The patched compiler can't work without this pull either, since it'd reference a non-existent typeinfo. What's the usual way to get the autotester to use both a patched dmd and druntime?

[yebblies]

There isn't a way, unless you feel like patching the autotester.

What kind of performance hit does the non-string hash give? Is it possible (without performance regressions) to remove the built-in typeinfo instead of adding a new one for const?

[quickfur]

@yebblies TBH I've no idea about the performance of string's toHash vs. const(char)[]'s toHash. It's code from before the D source code was put on github. I'll see if I can run some benchmarks later today when I have some free time.