maint: update copyright

[gnulib.git] / m4 / clock_time.m4

diff --git a/m4/clock_time.m4 b/m4/clock_time.m4
index 4133398..6c4a637 100644 (file)
--- a/m4/clock_time.m4
+++ b/m4/clock_time.m4
@@ -1,24 +1,31 @@
-# clock_time.m4 serial 1
-dnl Copyright (C) 2002 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License.  As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# clock_time.m4 serial 10
+dnl Copyright (C) 2002-2006, 2009-2014 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.
+
+# Check for clock_gettime and clock_settime, and set LIB_CLOCK_GETTIME.
+# For a program named, say foo, you should add a line like the following
+# in the corresponding Makefile.am file:
+# foo_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
 
-# Check for clock_gettime and clock_settime, and sets LIB_CLOCK_GETTIME.
 AC_DEFUN([gl_CLOCK_TIME],
 [
+  dnl Persuade glibc and Solaris <time.h> to declare these functions.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   # Solaris 2.5.1 needs -lposix4 to get the clock_gettime function.
   # Solaris 7 prefers the library name -lrt to the obsolescent name -lposix4.
-  
+
   # Save and restore LIBS so e.g., -lrt, isn't added to it.  Otherwise, *all*
   # programs in the package would end up linked with that potentially-shared
   # library, inducing unnecessary run-time overhead.
-  fetish_saved_libs=$LIBS
-    AC_SEARCH_LIBS(clock_gettime, [rt posix4],
-                   [LIB_CLOCK_GETTIME=$ac_cv_search_clock_gettime])
-    AC_SUBST(LIB_CLOCK_GETTIME)
-    AC_CHECK_FUNCS(clock_gettime clock_settime)
-  LIBS=$fetish_saved_libs
+  LIB_CLOCK_GETTIME=
+  AC_SUBST([LIB_CLOCK_GETTIME])
+  gl_saved_libs=$LIBS
+    AC_SEARCH_LIBS([clock_gettime], [rt posix4],
+                   [test "$ac_cv_search_clock_gettime" = "none required" ||
+                    LIB_CLOCK_GETTIME=$ac_cv_search_clock_gettime])
+    AC_CHECK_FUNCS([clock_gettime clock_settime])
+  LIBS=$gl_saved_libs
 ])