Here's how I got gambit working on the OLPC.
As root: yum install gcc yum install glibc-headers yum install make
As user olpc (the user account on the machine): curl -O http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/source/gambc-v4_1_2... tar xvzf gambc-v4_1_2.tgz cd gambc-v4_1_2 ./configure --prefix=/home/olpc/local/Gambit-C make make install
It really is that simple. This gets you a working Gambit binary that will run from inside the Terminal activity. It's not yet its own activity, and so will not run from the Sugar user interface; I think it's a noble goal to rectify that situation.
The Gambit compiler is not terribly useful, of course, without a C compiler, which the stock XO lacks, which presents problems of its own when bundling Gambit as an activity.
--Jeff