configure.ac: check for clock_gettime and CLOCK_MONOTONIC

diff --git a/Makefile b/Makefile
index 06e5d24312e47e9a6e7e33def74c70f54c21f2e1..1bbf5f950688be8bd8208dca57b3bb1739158e6e 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -343,6 +343,8 @@ all::
 # return NULL when it receives a bogus time_t.
 #
 # Define HAVE_CLOCK_GETTIME if your platform has clock_gettime in librt.
+#
+# Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC in librt.
 
 GIT-VERSION-FILE: FORCE
        @$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1402,6 +1404,10 @@ ifdef HAVE_CLOCK_GETTIME
        EXTLIBS += -lrt
 endif
 
+ifdef HAVE_CLOCK_MONOTONIC
+       BASIC_CFLAGS += -DHAVE_CLOCK_MONOTONIC
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif