This is actually caught by -Werror=format that is enabled by default.

$ sh ./configure --with-debug-level=slowdebug --with-boot-jdk=/home/shade/Install/jdk16-16.0.2-ea/ --openjdk-target=sparc64-linux-gnu --with-sysroot=/chroots/sparc64/ --with-jvm-variants=zero
$ make images

/home/shade/trunks/jdk/src/hotspot/os/posix/signals_posix.cpp: In static member function 'static void os::print_siginfo(outputStream*, const void*)':
/home/shade/trunks/jdk/src/hotspot/os/posix/signals_posix.cpp:1148:29: error: format '%ld' expects argument of type 'long int', but argument 3 has type 'int' [-Werror=format=]
 1148 | os->print(", si_band: %ld", si->si_band);
      | ~~^
      | |
      | long int
      | %d

man sigaction says:

siginfo_t {
    ...
               long si_band; /* Band event (was int in
                                         glibc 2.3.2 and earlier) */
    ...
}

Apparently reported as [glibc bug #23821](https://sourceware.org/bugzilla/show_bug.cgi?id=23821), and glibc maintainers decided not to fix it. So, we can still make a defensive cast to (long), which would be no-op if the type is in fact long.