Found the following significant warnings:
  ./glpkAPI.h:81:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:84:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:87:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:101:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:104:21: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:107:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:460:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./glpkAPI.h:491:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:433:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:446:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:459:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:722:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:791:21: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:825:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  glpkAPI.c:3400:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
See '/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/glpkAPI.Rcheck/00install.out' for details.