on the fortran source code of L-BFGS-B gave me linker errors on my mac OS X 10.6 machine:
invalid parameter driver1.o Undefined symbols: "_s_wsle", referenced from: _subsm_ in routines.o ....
I fixed this by installing g77, following these instructions.
Then changed the value of F77 in the makefile of L-BFGS-B:
#FC = f77 FC = g77
produced i386 executables and object files.
Note: I’m not sure what you would need to change to produce x86_64 files, luckily for me I wanted i386 all along.
Update: So the examples that g77 creates above work fine. But when I tried to call the fortran subroutines from c or cpp code I got weird errors. To solve this I switched gears and opted to use f2c/f77 and universal binaries, this so far is working much better.