Errors while compiling libdw

When compiling the RTS in a validate build, I see

rts/Libdw.c: In function ‘set_initial_registers’:

rts/Libdw.c:316:12: error:
     warning: ‘regs’ may be used uninitialized [-Wmaybe-uninitialized]
      316 |     return dwfl_thread_state_registers(thread, 0, 17, regs);
          |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    |
316 |     return dwfl_thread_state_registers(thread, 0, 17, regs);
    |            ^

In file included from rts/Libdw.c:15:0: error:

/nix/store/js14rv1j3yfqh0yc9x8p6r83xcs5x3vv-elfutils-0.187-dev/include/elfutils/libdwfl.h:745:6: error:
     note: by argument 4 of type ‘const Dwarf_Word *’ {aka ‘const long unsigned int *’} to ‘dwfl_thread_state_registers’ declared here
      745 | bool dwfl_thread_state_registers (Dwfl_Thread *thread, int firstreg,
          |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    |
745 | bool dwfl_thread_state_registers (Dwfl_Thread *thread, int firstreg,
    |      ^

rts/Libdw.c:293:16: error:
     note: ‘regs’ declared here
      293 |     Dwarf_Word regs[17];
          |                ^~~~
    |
293 |     Dwarf_Word regs[17];
    |                ^
rts/Libdw.c: At top level:
cc1: note: unrecognized command-line option ‘-Wno-nonportable-include-path’ may have been intended to silence earlier diagnostics

But the build seems to succeed anyway.