[MLton] problem building from svn checkout

[Stephen Weeks]

> after a svn checkout as per instructions on the webpage, a make all
> dies with the following error on the second round of compilation.

Hmmm.  I just did a clean svn checkout and full bootstrap without
problems.  Must be some difference in our environments.

> Error: front-end/mlb.lex.sml 1822.20.
>   Undefined structure Unsafe.
> Error: front-end/mlb.lex.sml 1838.36.
>   Undefined structure Unsafe.
> Error: front-end/mlb.lex.sml 1840.27.
>   Undefined structure Unsafe.

I can't quite pin down your exact problem, but it looks like it's due
to a combination of using an old mllex that generates code referring
to Unsafe and failure of the hack in mlton/front-end/sources.mlb (line
19-26) to make Unsafe available.  Since 20041109, mllex generates code
for the standard basis; so, you could get by simply by using a more
recent mllex.  But I'd like to understand the other problem before you
do so.

The only way I see that the hack in front-end/sources.mlb failing is
if SML_LIB is pointing in some strange place.  But, I would expect
that to show up as an error in the MLB not being able to find
unsafe.mlb or something like that.  Further, your error happened on
the second round of compilation, so it was using the just-built MLton,
which should have all the build/lib stuff in place, in particular
mlb-path-map.  So, I am stumped.  Perhaps you could investigate a bit
more where unsafe.mlb is coming from and why it isn't making Unsafe
available.

Input from anyone else able to recreate the problem would also be
helpful.