tests: posix: signal: account for ANSI / ISO C signal bits

The `signal()` function was part of ANSI-C and predates
POSIX, so it should be visible (even if it completely
unsupported in Zephyr currently).

The `sig_atomic_t` type is part of ISO C, regardless of
whether POSIX is enabled.

Signed-off-by: Christopher Friedt <cfriedt@meta.com>

tests/posix/headers/prj.conf

@@ -18,3 +18,4 @@ CONFIG_POSIX_CLOCK=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_EVENTFD=y
 CONFIG_GETOPT=y
+CONFIG_POSIX_SIGNAL=y

tests/posix/headers/src/signal_h.c

@@ -19,12 +19,17 @@
  */
 ZTEST(posix_headers, test_signal_h)
 {
+ /* part of ANSI C */
+ zassert_not_null(signal);
+ /* part of ISO C */
+ zassert_not_equal(sizeof(sig_atomic_t), 0);
+
+#ifdef CONFIG_POSIX_API
  /* zassert_not_equal(-1, SIG_DFL); */ /* not implemented */
  /* zassert_not_equal(-1, SIG_ERR); */ /* not implemented */
  /* zassert_not_equal(-1, SIG_HOLD); */ /* not implemented */
  /* zassert_not_equal(-1, SIG_IGN); */ /* not implemented */
 
- /* zassert_not_equal((sig_atomic_t)-1, (sig_atomic_t)0); */ /* not implemented */
  /* zassert_not_equal((pid_t)-1, (pid_t)0); */ /* not implemented */
 
  zassert_not_equal(-1, offsetof(struct sigevent, sigev_notify));
@@ -130,7 +135,6 @@ ZTEST(posix_headers, test_signal_h)
  /* zassert_not_equal(-1, SI_ASYNCIO); */ /* not implemented */
  /* zassert_not_equal(-1, SI_MESGQ); */ /* not implemented */
 
-#ifdef CONFIG_POSIX_SIGNAL
  zassert_true(SIGRTMIN >= 0);
  zassert_true(SIGRTMAX >= SIGRTMIN);
  zassert_not_equal(-1, SIGABRT);
@@ -157,38 +161,34 @@ ZTEST(posix_headers, test_signal_h)
  zassert_not_equal(-1, SIGURG);
  zassert_not_equal(-1, SIGXCPU);
  zassert_not_equal(-1, SIGXFSZ);
- zassert_not_equal(((sigset_t){.sig[0] = 0}).sig[0], ((sigset_t){.sig[0] = -1}).sig[0]);
+ zassert_not_equal(sizeof(sigset_t), 0);
  zassert_not_null(sigemptyset);
  zassert_not_null(sigfillset);
  zassert_not_null(sigaddset);
  zassert_not_null(sigdelset);
  zassert_not_null(sigismember);
  zassert_not_null(strsignal);
-#endif /* CONFIG_POSIX_SIGNAL */
-
- if (IS_ENABLED(CONFIG_POSIX_API)) {
- /* zassert_not_null(kill); */ /* not implemented */
- /* zassert_not_null(killpg); */ /* not implemented */
- /* zassert_not_null(psiginfo); */ /* not implemented */
- /* zassert_not_null(psignal); */ /* not implemented */
- /* zassert_not_null(pthread_kill); */ /* not implemented */
- /* zassert_not_null(pthread_sigmask); */ /* not implemented */
- /* zassert_not_null(raise); */ /* not implemented */
- /* zassert_not_null(sigaction); */ /* not implemented */
- /* zassert_not_null(sigaltstack); */ /* not implemented */
- /* zassert_not_null(sighold); */ /* not implemented */
- /* zassert_not_null(sigignore); */ /* not implemented */
- /* zassert_not_null(siginterrupt); */ /* not implemented */
- /* zassert_not_null(signal); */ /* not implemented */
- /* zassert_not_null(sigpause); */ /* not implemented */
- /* zassert_not_null(sigpending); */ /* not implemented */
- /* zassert_not_null(sigprocmask); */ /* not implemented */
- /* zassert_not_null(sigqueue); */ /* not implemented */
- /* zassert_not_null(sigrelse); */ /* not implemented */
- /* zassert_not_null(sigset); */ /* not implemented */
- /* zassert_not_null(sigsuspend); */ /* not implemented */
- /* zassert_not_null(sigtimedwait); */ /* not implemented */
- /* zassert_not_null(sigwait); */ /* not implemented */
- /* zassert_not_null(sigwaitinfo); */ /* not implemented */
- }
+ /* zassert_not_null(kill); */ /* not implemented */
+ /* zassert_not_null(killpg); */ /* not implemented */
+ /* zassert_not_null(psiginfo); */ /* not implemented */
+ /* zassert_not_null(psignal); */ /* not implemented */
+ /* zassert_not_null(pthread_kill); */ /* not implemented */
+ /* zassert_not_null(pthread_sigmask); */ /* not implemented */
+ /* zassert_not_null(raise); */ /* not implemented */
+ /* zassert_not_null(sigaction); */ /* not implemented */
+ /* zassert_not_null(sigaltstack); */ /* not implemented */
+ /* zassert_not_null(sighold); */ /* not implemented */
+ /* zassert_not_null(sigignore); */ /* not implemented */
+ /* zassert_not_null(siginterrupt); */ /* not implemented */
+ /* zassert_not_null(sigpause); */ /* not implemented */
+ /* zassert_not_null(sigpending); */ /* not implemented */
+ /* zassert_not_null(sigprocmask); */ /* not implemented */
+ /* zassert_not_null(sigqueue); */ /* not implemented */
+ /* zassert_not_null(sigrelse); */ /* not implemented */
+ /* zassert_not_null(sigset); */ /* not implemented */
+ /* zassert_not_null(sigsuspend); */ /* not implemented */
+ /* zassert_not_null(sigtimedwait); */ /* not implemented */
+ /* zassert_not_null(sigwait); */ /* not implemented */
+ /* zassert_not_null(sigwaitinfo); */ /* not implemented */
+#endif
 }