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Fix murmurhash2 when string length is a multiple of a 4

The first h *= m after the loop should only happen for len % 4 != 0.

--- a/lib/std/hashfuncs.myr

+++ b/lib/std/hashfuncs.myr

@@ -121,17 +121,19 @@

 	match data.len

 	| 3:

 		h ^= (data[2] : uint32) << 16

-		h ^= (data[1] : uint32) <<8

+		h ^= (data[1] : uint32) << 8

 		h ^= (data[0] : uint32)

+		h *= m

 	| 2:

-		h ^= (data[1] : uint32) <<8

+		h ^= (data[1] : uint32) << 8

 		h ^= (data[0] : uint32)

+		h *= m

 	| 1:

 		h ^= (data[0] : uint32)

+		h *= m

 	| 0:	/* nothing */

 	| _:	die("0 < len < 4 must be true")

 	;;

-	h *= m

 	h ^= h >> 13

 	h *= m

--- a/util/htab.c

+++ b/util/htab.c

@@ -322,10 +322,8 @@

 	case 3:	h ^= p[2] << 16;

 	case 2:	h ^= p[1] << 8;

 	case 1:	h ^= p[0] << 0;

-	default:

-		break;

-	};

-	h *= m;

+		h *= m;

+	}

 	h ^= h >> 13;

 	h *= m;