[MLton] power pc "port"

[Matthew Fluet]

> Right now, I'm building libmlton as a dynamic lib because static linking
> is giving me other problems.  So this would explain it.

Yes.  Looking at things, I think the whole "spawn.h" is a hack.  Under the
new platform.h setup, I think that cygwin.h and mingw.h should
 #define HAS_SPAWN TRUE
and the other unix-y platforms should
 #define HAS_SPAWN FALSE
and the spawne.c and spawnp.c files should
 #if HAS_SPAWN
 ...
 #endif /* HAS_SPAWN */
their contents.  We'd be much better getting linker errors claiming to not
find MLton_Process_spawn{e,p} than linker errors not finding spawnv{e,p}.

In any case, you ought to be able to make some progress by some variation
of the above -- essentially eliminating the spawn{e,p}.c code from the Mac
OS X platform.

> Other than the situation with spawnve/p functions, is there any particular
> reason why libmlton and libgdtoa are static rather than dynamic?

Probably, but I don't know.