[MLton] Re: [MLton-commit] r4545

[Matthew Fluet]

> Used the same gcc-specific attributes to define "pointer" to be 4-byte
> aligned as we did for "Pointer".  This eliminated all but six of the
> warning about "cast increases required alignment of target type".

This change is wrong for (at least) the uses of pointer in the profiling 
code.  The GC_sourceLabel.label field corresponds to a code label, which 
(on x86) isn't necessarily 4-byte aligned.  Likewise in GC_handleSigProf, 
the program counter (on x86) isn't necessarily 4-byte aligned.