gettimeofday: port recent C++ fix to Emacs

[gnulib.git] / m4 / timer_time.m4

diff --git a/m4/timer_time.m4 b/m4/timer_time.m4
index 00bc2fe..ea018f9 100644 (file)
--- a/m4/timer_time.m4
+++ b/m4/timer_time.m4
@@ -1,5 +1,5 @@
-# timer_time.m4 serial 1
-dnl Copyright (C) 2011 Free Software Foundation, Inc.
+# timer_time.m4 serial 2
+dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -11,6 +11,7 @@ AC_DEFUN([gl_TIMER_TIME],
   dnl Based on clock_time.m4. See details there.
 
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([gl_THREADLIB])
 
   LIB_TIMER_TIME=
   AC_SUBST([LIB_TIMER_TIME])
@@ -18,6 +19,21 @@ AC_DEFUN([gl_TIMER_TIME],
     AC_SEARCH_LIBS([timer_settime], [rt posix4],
                    [test "$ac_cv_search_timer_settime" = "none required" ||
                     LIB_TIMER_TIME=$ac_cv_search_timer_settime])
+    dnl GLIBC uses threads to emulate posix timers when kernel support
+    dnl is not available (like Linux < 2.6 or when used with kFreeBSD)
+    dnl Now the pthread lib is linked automatically in the normal case,
+    dnl but when linking statically, it needs to be explicitly specified.
+    AC_EGREP_CPP([Thread],
+      [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 2) || (__GLIBC__ > 2)) \
+     && !defined __UCLIBC__
+  Thread emulation available
+ #endif
+#endif
+      ],
+      [LIB_TIMER_TIME="$LIB_TIMER_TIME $LIBMULTITHREAD"])
     AC_CHECK_FUNCS([timer_settime])
   LIBS=$gl_saved_libs
 ])