Boost.Jam Compile Fix

[nobody]

When I was trying to get Boost.Jam to compile for
mingw, I had lots (and lots) of problems.  Mainly, the
fact that the boost-build.jam file was not made right.
So, I edited the file and made a couple modifications
to the build.sh script for the sake of ease too. All
this is in the tools/build/jam_src directory, by the
way. You can just overwrite the files included in the
directory and execute as normal. If you have problems
in MSYS, use the Windows command line. This won't break
other compiles, I don't think, but I wouldn't go about
inserting it into the tree without a good looking over.
I also included a list of the changes I made for your
reference.

Ryan Egesdahl
deriamis[at]yahoo[dot]com

[biochimia]

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user_id=840777

Going over the CVS log for bjam's build scripts it looks
like everything is working and has been tested for both
MinGW and MSYS.

Reviewing the proposed fixes it seems the approach taken was
possibly not the best one. build.bat could have been used
with MinGW, instead of build.sh.

Closing as fixed.