Found the following significant warnings:
  randomForestSRC.h:412:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:413:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:609:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:610:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:612:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:613:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:924:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1002:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1163:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1164:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1355:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1509:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1514:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1515:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1874:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1875:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1888:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1895:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1906:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1907:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1908:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1909:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1910:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:1911:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:2003:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:2004:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:2220:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:2222:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.h:2239:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:3073:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:3075:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:3079:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:3180:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:6468:16: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:6480:22: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:7682:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:9276:13: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:11617:18: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:11621:18: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  splitCustom.h:22:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:16021:16: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:21043:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:21089:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:21475:18: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:28671:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:28988:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29438:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29485:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29504:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29517:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29522:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29545:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:29554:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:31136:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:31199:11: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:34940:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:34953:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  randomForestSRC.c:35129:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  splitCustom.c:22:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/randomForestSRC.Rcheck/00install.out’ for details.
* used C compiler: ‘gcc-12 (Debian 12.2.0-13) 12.2.0’