FX's nightly builds broken on Pentium-1

[FX Coudert]

> Program received signal SIGSEGV, Segmentation fault.
> mpfr_set_default_prec (prec=128) at set_dfl_prec.c:32
> 32      set_dfl_prec.c: No such file or directory.
>         in set_dfl_prec.c
> (gdb) where
> #0  mpfr_set_default_prec (prec=128) at set_dfl_prec.c:32
> (gdb)

I've looked into it some more, and built some new GMP and MPFR  
libraries, using --build=i386-pc-linux-gnu and --host likewise for  
GMP, and explicitly adding CFLAGS='-march=i386 -mcpu=i386' for MPFR.  
I also changed the script so that it explicitly builds for --host=  
i386-pc-linux-gnu.

If tonight's build still fail, then I don't see any other reason than  
bad karma :(

FX