Patch attached for a new file algebra.scm containing fplll and mpfrcx.

I also tried to add gmp-ecm, but it is only downloadable over https://,
which is not yet implemented.

Then I would like to add Pari/GP, but it uses non-standard commands
("./Configure" instead of "./configure", "make all" instead of "make",
"make dobench" instead of "make check"; only "make install" is the same).
Can this be done easily?

Andreas