libsystemd: check if _POSIX_C_SOURCE is defined

This can cause issues if sd-event.h is included in a source file that doesn't
define _POSIX_C_SOURCE and is compiled with -Wundef.

diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index 787a12f2416b7fe16565abbe0015e827807ffc51..7bb8609376c43e6f42d6b1c1bcb2050ac0ff4a26 100644 (file)
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -71,7 +71,7 @@ typedef int (*sd_event_handler_t)(sd_event_source *s, void *userdata);
 typedef int (*sd_event_io_handler_t)(sd_event_source *s, int fd, uint32_t revents, void *userdata);
 typedef int (*sd_event_time_handler_t)(sd_event_source *s, uint64_t usec, void *userdata);
 typedef int (*sd_event_signal_handler_t)(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata);
-#if defined _GNU_SOURCE || _POSIX_C_SOURCE >= 199309L
+#if defined _GNU_SOURCE || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 199309L)
 typedef int (*sd_event_child_handler_t)(sd_event_source *s, const siginfo_t *si, void *userdata);
 #else
 typedef void* sd_event_child_handler_t;