use of MPL'ed code on closed platforms

Hi all,

I am considering incorporating the SpiderMonkey code into a commercial
project that will be distributed on some closed platforms -- that is,
hardware platforms for which a compiler and other development tools
are not publicly available.

Is there anything in the MPL that would prohibit this?  From my very
naive reading of the license, it seems that build scripts and the like
must be distributed along with the modified code, but it is not
required that end users actually be able to build the modified code
for all platforms on which binaries are distributed.  Is that correct,
or is there potentially some trouble here?

For what it's worth, the modifiications that would be made would
likely be generic cross-platform things like hooks for custom memory
management and perhaps some minor language extensions.  Thus they
would be very usable on standard platforms.

Thanks for any help you can offer!
-Ethan