[Bug]: sig_t is not portable

[mtelka]

Describe the issue

Compilation of tests fails on OpenIndiana due to sig_t:

/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/time/clock_test.cc: In function 'bool {anonymous}::SleepForBounded(absl::lts_20240116::Duration, absl::lts_20240116::Duration, absl::lts_20240116::Duration, absl::lts_20240116::Duration, AlarmPolicy, int*)':
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/time/clock_test.cc:62:5: error: 'sig_t' was not declared in this scope
   62 |     sig_t old_alarm = SIG_DFL;
      |     ^~~~~
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/time/clock_test.cc:65:7: error: 'old_alarm' was not declared in this scope
   65 |       old_alarm = signal(SIGALRM, AlarmHandler);
      |       ^~~~~~~~~
/data/builds/oi-userland/components/library/abseil-cpp/abseil-cpp-20240116.3/absl/time/clock_test.cc:77:23: error: 'old_alarm' was not declared in this scope
   77 |       signal(SIGALRM, old_alarm);
      |                       ^~~~~~~~~

Steps to reproduce the problem

Compile abseil-cpp 20240116.3 with -DABSL_BUILD_TESTING=ON and -DABSL_USE_EXTERNAL_GOOGLETEST=ON on OpenIndiana.

What version of Abseil are you using?

20240116.3

What operating system and version are you using?

OpenIndiana Hipster (an illumos distro)

What compiler and version are you using?

$ gcc --version
gcc (OpenIndiana 14.2.0-oi-1) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$

What build system are you using?

cmake version 3.31.5

Additional context

No response

[mtelka]

This fixes the problem:

--- absl/time/clock_test.cc.orig
+++ absl/time/clock_test.cc
@@ -18,7 +18,7 @@
 #if defined(ABSL_HAVE_ALARM)
 #include <signal.h>
 #include <unistd.h>
-#ifdef _AIX
+#if defined(_AIX) || defined(__illumos__)
 // sig_t is not defined in AIX.
 typedef void (*sig_t)(int);
 #endif