Found the following significant warnings:
  ./settings.h:60:42: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./cstringr.h:50:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./cstringr.h:51:26: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./cstringr.h:52:27: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./cstringr.h:53:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./cstringr.h:54:26: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./alike.h:189:48: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./alike.h:225:36: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  alike.c:53:50: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  alike.c:77:34: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  all-bw.c:25:28: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  assumptions.c:33:28: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  cstringrtest.c:28:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  cstringrtest.c:35:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  cstringrtest.c:42:22: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  cstringrtest.c:51:24: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  cstringrtest.c:65:25: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./validate.h:92:30: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./validate.h:94:21: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  ./validate.h:130:25: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  recurse.c:82:46: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  settings.c:26:40: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
See ‘/data/gannet/ripley/R/packages/tests-clang/vetr.Rcheck/00install.out’ for details.
* used C compiler: ‘clang version 15.0.6’