Test -lrt for sched_yield

Apparently, this is needed in some Solaris versions.

Author: Oskari Saarenmaa

configure

@@ -8227,6 +8227,63 @@ if test "$ac_res" != no; then :
 
 fi
 
+# Required for thread_test.c on Solaris
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing sched_yield" >&5
+$as_echo_n "checking for library containing sched_yield... " >&6; }
+if ${ac_cv_search_sched_yield+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sched_yield ();
+int
+main ()
+{
+return sched_yield ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' rt; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_sched_yield=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_sched_yield+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_sched_yield+:} false; then :
+
+else
+  ac_cv_search_sched_yield=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_sched_yield" >&5
+$as_echo "$ac_cv_search_sched_yield" >&6; }
+ac_res=$ac_cv_search_sched_yield
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+fi
+
 # Required for thread_test.c on Solaris 2.5:
 # Other ports use it too (HP-UX) so test unconditionally
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing gethostbyname_r" >&5

configure.in

@@ -974,6 +974,8 @@ AC_SEARCH_LIBS(shm_open, rt)
 AC_SEARCH_LIBS(shm_unlink, rt)
 # Solaris:
 AC_SEARCH_LIBS(fdatasync, [rt posix4])
+# Required for thread_test.c on Solaris
+AC_SEARCH_LIBS(sched_yield, rt)
 # Required for thread_test.c on Solaris 2.5:
 # Other ports use it too (HP-UX) so test unconditionally
 AC_SEARCH_LIBS(gethostbyname_r, nsl)