f95

Because that particular Tiger build is broken and segfaults on R
sources.

You can find a working binary for gcc-4.0 with gfortran that will  
build a working R and Octave at http://www.swarm.org/wiki/ 
Swarm:_MacOS_X_binaries

This compiler was built from Apple sources with tag apple-gcc-5017.   
The Fortran components are updated from the gcc-4_0-branch of the cvs  
as at 19 May 2005.

You will probably need to set up environment variables CC, CXX and  
F77 to get configure scripts to recognise it.

Bill Northcott