[3.8] bpo-35455: Fix thread_time for Solaris OS (GH-11118). (GH-23145)

(cherry picked from commit 9568622)

Co-authored-by: Jakub Kulík <Kulikjak@gmail.com>

Author: kulikjak

Misc/NEWS.d/next/Library/2020-11-02-14-10-48.bpo-35455.Q1xTIo.rst

@@ -0,0 +1,3 @@
+On Solaris, :func:`~time.thread_time` is now implemented with
+``gethrvtime()`` because ``clock_gettime(CLOCK_THREAD_CPUTIME_ID)`` is not
+always available. Patch by Jakub Kulik.

Modules/timemodule.c

@@ -1344,6 +1344,23 @@ _PyTime_GetThreadTimeWithInfo(_PyTime_t *tp, _Py_clock_info_t *info)
     return 0;
 }
 
+#elif defined(__sun) && defined(__SVR4)
+#define HAVE_THREAD_TIME
+static int
+_PyTime_GetThreadTimeWithInfo(_PyTime_t *tp, _Py_clock_info_t *info)
+{
+    /* bpo-35455: On Solaris, CLOCK_THREAD_CPUTIME_ID clock is not always
+       available; use gethrvtime() to substitute this functionality. */
+    if (info) {
+        info->implementation = "gethrvtime()";
+        info->resolution = 1e-9;
+        info->monotonic = 1;
+        info->adjustable = 0;
+    }
+    *tp = _PyTime_FromNanoseconds(gethrvtime());
+    return 0;
+}
+
 #elif defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_PROCESS_CPUTIME_ID)
 #define HAVE_THREAD_TIME
 static int