[gnome-builder] build: add checks for sched_getcpu() and use them

[Christian Hergert <chergert src gnome org>]

commit 2e506f0b597500bf44a8ebbe2653399bc8255f2a
Author: Christian Hergert <chergert redhat com>
Date:   Mon Nov 23 14:35:06 2020 -0800

    build: add checks for sched_getcpu() and use them

 meson.build |  3 +++
 src/main.c  | 14 ++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 7a5c7fe6c..e1f7f0a57 100644
--- a/meson.build
+++ b/meson.build
@@ -279,6 +279,9 @@ check_functions = [
   ['HAVE_PTSNAME', 'ptsname'],
   ['HAVE_PTSNAME_R', 'ptsname_r'],
   ['HAVE_UNLOCKPT', 'unlockpt'],
+
+  # scheduling
+  ['HAVE_SCHED_GETCPU', 'sched_getcpu'],
 ]
 foreach func: check_functions
   config_h.set(func[0], cc.has_function(func[1]))
diff --git a/src/main.c b/src/main.c
index c68c86bf6..072acb6a1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -49,6 +49,16 @@
 static SysprofCaptureWriter *trace_writer;
 static G_LOCK_DEFINE (tracer);
 
+static inline int
+current_cpu (void)
+{
+#ifdef HAVE_SCHED_GETCPU
+  return sched_getcpu ();
+#else
+  return 0;
+#endif
+}
+
 static void
 trace_load (void)
 {
@@ -76,7 +86,7 @@ trace_function (const gchar    *func,
       G_LOCK (tracer);
       sysprof_capture_writer_add_mark (trace_writer,
                                        begin_time_usec * 1000L,
-                                       sched_getcpu (),
+                                       current_cpu (),
                                        getpid (),
                                        (end_time_usec - begin_time_usec) * 1000L,
                                        "tracing",
@@ -96,7 +106,7 @@ trace_log (GLogLevelFlags  log_level,
       G_LOCK (tracer);
       sysprof_capture_writer_add_log (trace_writer,
                                       SYSPROF_CAPTURE_CURRENT_TIME,
-                                      sched_getcpu (),
+                                      current_cpu (),
                                       getpid (),
                                       log_level,
                                       domain,