GLU:TESS-PROPERTY is broken for :BOUNDARY-ONLY

[Gleefre]

When calling

(glu:tess-property tesselator :boundary-only t)

an error is signalled:

debugger invoked on a SIMPLE-ERROR in thread
#<THREAD tid=1149402 "main thread" RUNNING {1001478093}>:
  CL-OPENGL-BINDINGS:BOOLEAN is not a foreign enum type.

Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [ABORT] Exit debugger, returning to top level.

(CFFI:FOREIGN-ENUM-VALUE CL-OPENGL-BINDINGS:BOOLEAN T :ERRORP T)
   source: (ERROR "~S is not a foreign enum type." TYPE)

P.S. Here is the offending line of code: https://github.com/3b/cl-opengl/blob/master/glu/glu.lisp#L326