[dmd-beta] beta for 1.057 and 2.041

[Don Clugston]

These bugs are fixed but not listed in the changelog:

bugzilla 3453 Linking order affects proper execution (Mac OSX only)
bugzilla 3491 typeof( (string[string]).init)) ==
AssociativeArray!(string, string), doesn't implicitly convert to
string[string].
bugzilla 3692 ICE(mtype.c) with associative arrays when std.variant is imported