Found the following significant warnings:
  htree.c:126:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:135:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:324:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:362:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:408:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:517:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:693:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:711:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:813:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1476:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1494:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1528:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1679:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1754:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1839:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1869:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1909:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:2906:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:3696:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  init.c:13:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/htree.Rcheck/00install.out’ for details.
* used C compiler: ‘gcc-12 (Debian 12.2.0-14) 12.2.0’
Found the following significant warnings:
  htree.c:126:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:135:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:324:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:362:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:408:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:517:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:693:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:711:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:813:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1476:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1494:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1528:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1679:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1754:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1839:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1869:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1909:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:2906:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:3696:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  init.c:13:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
See ‘/data/gannet/ripley/R/packages/tests-devel/htree.Rcheck/00install.out’ for details.
* used C compiler: ‘gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4)’
Found the following significant warnings:
  htree.c:126:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:135:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:324:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:362:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:408:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:517:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:693:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:711:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:813:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1476:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1494:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1528:8: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1679:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1754:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1839:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1869:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:1909:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:2906:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  htree.c:3696:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  init.c:13:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
See ‘/home/hornik/tmp/R.check/r-patched-gcc/Work/PKGS/htree.Rcheck/00install.out’ for details.
* used C compiler: ‘gcc-11 (Debian 11.3.0-12) 11.3.0’