Timestamps: Default to nanosecond-precision timestamps if clock_getti…

…me()

is available.  Inspired by POSIX 2008 deprecating gettimeofday().

configure

@@ -7412,16 +7412,6 @@ done
 
 
 
-# Check whether --enable-nanotimestamp was given.
-if test "${enable_nanotimestamp+set}" = set; then :
-  enableval=$enable_nanotimestamp;
-fi
-
-if test "x$enable_nanotimestamp" = xyes; then
-    $as_echo "#define HAVE_NANOTIMESTAMP_ENABLED 1" >>confdefs.h
-
-fi
-
 for ac_header in time.h
 do :
   ac_fn_cxx_check_header_mongrel "$LINENO" "time.h" "ac_cv_header_time_h" "$ac_includes_default"
@@ -7517,6 +7507,7 @@ _ACEOF
 
 fi
 
+    have_clock_gettime=no
     ac_fn_cxx_check_decl "$LINENO" "clock_gettime" "ac_cv_have_decl_clock_gettime" "#ifdef HAVE_TIME_H
 # include <time.h>
 #endif
@@ -7588,13 +7579,29 @@ if test "$ac_res" != no; then :
 
 $as_echo "#define HAVE_CLOCK_GETTIME 1" >>confdefs.h
 
+	have_clock_gettime=yes
 fi
 
     POSIX_CLOCK_LIBS="$LIBS"
 
     LIBS="$SAVELIBS"
 
 
+# Check whether --enable-nanotimestamp was given.
+if test "${enable_nanotimestamp+set}" = set; then :
+  enableval=$enable_nanotimestamp;
+fi
+
+# Default to nanosecond-precision timestamps if clock_gettime is available.
+if test "x$enable_nanotimestamp" = x -a "x$have_clock_gettime" = xyes; then
+    enable_nanotimestamp=yes
+fi
+if test "x$enable_nanotimestamp" = xyes; then
+
+$as_echo "#define HAVE_NANOTIMESTAMP_ENABLED 1" >>confdefs.h
+
+fi
+
 
 
 # Check whether --enable-tools was given.

configure.in

@@ -437,11 +437,6 @@ dnl
 dnl timestamps
 dnl
 
-AC_ARG_ENABLE(nanotimestamp, [  --enable-nanotimestamp  enable nanosecond timestamps])
-if test "x$enable_nanotimestamp" = xyes; then
-    AC_DEFINE(HAVE_NANOTIMESTAMP_ENABLED)
-fi
-
 AC_CHECK_HEADERS(time.h)
 AC_CHECK_SIZEOF([struct timeval])
 AC_CHECK_TYPES([struct timespec], have_timespec=yes, have_timespec=no)
@@ -450,6 +445,15 @@ if test "x$have_timespec" = xyes; then
 fi
 CLICK_CHECK_POSIX_CLOCKS
 
+AC_ARG_ENABLE(nanotimestamp, [  --enable-nanotimestamp  enable nanosecond timestamps])
+# Default to nanosecond-precision timestamps if clock_gettime is available.
+if test "x$enable_nanotimestamp" = x -a "x$have_clock_gettime" = xyes; then
+    enable_nanotimestamp=yes
+fi
+if test "x$enable_nanotimestamp" = xyes; then
+    AC_DEFINE([HAVE_NANOTIMESTAMP_ENABLED], [1], [Define if nanosecond-granularity timestamps are enabled.])
+fi
+
 
 dnl
 dnl check whether tools should be built for host or build

m4/click.m4

@@ -797,12 +797,14 @@ dnl POSIX_CLOCK_LIBS.
 dnl
 
 AC_DEFUN([CLICK_CHECK_POSIX_CLOCKS], [
+    have_clock_gettime=no
     AC_CHECK_DECLS([clock_gettime], [], [], [#ifdef HAVE_TIME_H
 # include <time.h>
 #endif])
     SAVELIBS="$LIBS"
     AC_SEARCH_LIBS([clock_gettime], [rt],
-	[AC_DEFINE([HAVE_CLOCK_GETTIME], [1], [Define if you have the clock_gettime function.])])
+	[AC_DEFINE([HAVE_CLOCK_GETTIME], [1], [Define if you have the clock_gettime function.])
+	have_clock_gettime=yes])
     POSIX_CLOCK_LIBS="$LIBS"
     AC_SUBST(POSIX_CLOCK_LIBS)
     LIBS="$SAVELIBS"