Found the following significant warnings:
  ./redefine.h:9:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./redefine.h:27:26: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:210:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:222:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:401:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  getdata.c:44:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./hash.h:15:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./hash.h:15:13: warning: a function declaration without a prototype is deprecated in all versions of C and is treated as a zero-parameter prototype in C2x, conflicting with a subsequent definition [-Wdeprecated-non-prototype]
  rcubist.c:40:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  redefine.c:46:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  redefine.c:191:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  redefine.c:209:15: warning: passing arguments to 'ht_destroy' without a prototype is deprecated in all versions of C and is not supported in C2x [-Wdeprecated-non-prototype]
  rulebasedmodels.c:197:11: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  rulebasedmodels.c:202:14: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  top.c:10:23: 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/Cubist.Rcheck/00install.out' for details.