Enable CPU profiling on Cygwin

* src/syssignal.h [CYGWIN] (PROFILER_CPU_SUPPORT): Revert previous
change that undefined this.
(SIGEV_SIGNAL): Ensure that this is defined as a macro.
* src/profiler.c [CYGWIN] (timer_getoverrun): Define as a macro on
  Cygwin.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/profiler.c b/src/profiler.c
index 185382c5bd8..d4c98a82657 100644
--- a/src/profiler.c
+++ b/src/profiler.c
@@ -217,6 +217,12 @@ static EMACS_INT current_sampling_interval;
 
 /* Signal handler for sampling profiler.  */
 
+/* timer_getoverrun is not implemented on Cygwin, but the following
+   seems to be good enough for profiling. */
+#ifdef CYGWIN
+#define timer_getoverrun(x) 0
+#endif
+
 static void
 handle_profiler_signal (int signal)
 {