[R-SIG-Mac] GNU Fortran 4.2, Apple build for Leopard

[Simon Urbanek]

For those interested, you can get GNU Fortran 4.2.1 (Apple build  
5531) for Mac OS X 10.5 here:

http://r.research.att.com/gfortran-42.pkg

This build will add Fortran capability to Apple's gcc 4.2 compilers.  
This is a real Apple-build of GNU Fortran based on Apple's gcc 4.2  
(build 5531) and GNU Fortran sources from the gcc 4.2.2 release (with  
minor tweaks to make them to live together). The above package just  
adds the Fortran files, so you must have Apple's gcc-4.2 already  
installed.

Requirements:
- Mac OS X 10.5 (Leopard)
- Apple gcc 4.2

**Important note**: remove all other existing GNU Fortran compilers  
from your system (including those in /usr/local such as the one  
supplied with R!). Due to the way libraries are searched, if another  
Fortran is found and it has a shared libgfortran library then that  
library will be used instead of the static one that comes with this  
compiler.

This build uses Apple's drivers (supports all special Apple flags)  
and is fully universal (supports all targets) and can be easily  
uninstalled (using gfortran-4.2-uninstall script). It lives in /usr  
as it becomes part of the system compiler.

The really good thing about this compiler is that the resulting  
programs don't need any non-system libraries, so they are full self- 
contained. This eliminates the hassle with libgfortran.dylib,  
different versions of libgcc etc. And, of course, R was tested and  
works well with this compiler.

Cheers,
Simon