Found the following significant warnings:
  fansi.h:190:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  assumptions.c:31:13: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  assumptions.c:45:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:66:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:72:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:73:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:74:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:75:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:76:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:87:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:98:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:99:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:100:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:101:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  fansi-ext.h:103:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:59:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:70:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:177:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:180:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:183:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  utils.c:186:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  write.c:323:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  write.c:370:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  write.c:377:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  write.c:386:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
  write.c:395:6: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/fansi.Rcheck/00install.out’ for details.
* used C compiler: ‘gcc-12 (Debian 12.2.0-13) 12.2.0’