Compiling a current coreutils on Debian GNU/Hurd from 2022, I get this
compilation error:

  CC       src/copy.o
../src/copy.c: In function 'set_author':
../src/copy.c:984:15: error: 'MACH_PORT_nullptr' undeclared (first use in this function); did you mean 'MACH_PORT_NULL'?
  984 |   if (file == MACH_PORT_nullptr)
      |               ^~~~~~~~~~~~~~~~~
      |               MACH_PORT_NULL
../src/copy.c:984:15: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [Makefile:12489: src/copy.o] Error 1

The attached patch fixes it.