Found the following significant warnings:
  ./defns.h:671:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./defns.h:761:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./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]
  attwinnow.c:51:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  classify.c:627:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  construct.c:62:26: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  construct.c:350:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  construct.c:380:14: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:177:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:288:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:300:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:475:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formrules.c:599:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formtree.c:62:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formtree.c:172:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  formtree.c:266:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  getdata.c:47:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  getdata.c:562:14: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  getnames.c:510:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  getnames.c:555:15: 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]
  implicitatt.c:226:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:249:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:271:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:305:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:337:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:357:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:377:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:397:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  implicitatt.c:543:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:197:29: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:263:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:448:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:521:23: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:592:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:675:12: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:778:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:866:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:908:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  modelfiles.c:957:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  prune.c:685:25: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  rc50.c:42:12: 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]
  rsample.c:59:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  rulebasedmodels.c:231:11: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  rulebasedmodels.c:236:14: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:171:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:274:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:383:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:493:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:627:21: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:743:29: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:767:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:854:21: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:931:19: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:1018:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:1054:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  siftrules.c:1100:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  subset.c:44:27: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  top.c:10:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:201:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:218:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:256:15: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:546:16: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:795:17: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  utility.c:835:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  xval.c:49:14: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  xval.c:183:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  xval.c:253:13: 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/C50.Rcheck/00install.out' for details.