G'day Patrick,

I suspect that the '-', in '/usr/local/gsl-1/lib', may be the cause of the problem. It's a special character in many places, and may be interpreted as such elsewhere.

[See how EXTRALIBS and LDLOADLIBS are missing the -L/usr/local/gsl-1/lib part, but otherwise follow your assignments. LD_RUN_PATH, with perhaps no effective assignment, might have retained its previous value or been assigned a default, i.e. /usr/lib.]

Some things to try: escape the dash; quote the path; create a symlink.