OBSD new libgsl not found

[Jason Stover]

After a fresh checkout, configure tells me I need gsl 1.8
or later, even though I have 1.11.

$ pkg-config --atleast-version 1.8 gsl
$ echo $?
0

$ pkg-config --cflags --libs gsl
-I/usr/local/include -L/usr/local/lib -lgsl -lgslcblas -lm

I may have an old copy of gsl somewhere, but not in the usual
/usr/lib or /usr/local/lib.

-Jason