upsmon.c:2437:17: error: incompatible function pointer types passing 'void (*)()' to parameter of type 'void (*)(int)' [-Werror,-Wincompatible-function-pointer-types-strict]
 2437 |         signal(SIGHUP, SIG_IGN);
      |                        ^~~~~~~
/usr/include/sys/iso/signal_iso.h:125:17: note: expanded from macro 'SIG_IGN'
  125 | #define SIG_IGN (void (*)())1
      |                 ^~~~~~~~~~~~~
/usr/include/iso/signal_iso.h:63:34: note: passing argument to parameter here
   63 | extern void (*signal(int, void (*)(int)))(int);
      |                                  ^