Merge pull request #534 from ii8/master

Set default alignment on powerpc64 to 8

Author: MatthewFluet

mlton/main/main.fun

@@ -199,6 +199,7 @@ fun defaultAlignIs8 () =
        | HPPA => true
        | IA64 => true
        | MIPS => true
+       | PowerPC64 => true
        | Sparc => true
        | S390 => true
        | _ => false