timer: Introduce osmo_clock_gettime to override clock_gettime

Change-Id: I5bebc6e01fc9d238065bc2517058f0ba85620349
diff --git a/src/Makefile.am b/src/Makefile.am
index 3d6e6f7..2641a97 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -13,7 +13,8 @@
 lib_LTLIBRARIES = libosmocore.la
 
 libosmocore_la_LIBADD = $(BACKTRACE_LIB) $(TALLOC_LIBS)
-libosmocore_la_SOURCES = timer.c timer_gettimeofday.c select.c signal.c msgb.c bits.c \
+libosmocore_la_SOURCES = timer.c timer_gettimeofday.c timer_clockgettime.c \
+			 select.c signal.c msgb.c bits.c \
 			 bitvec.c bitcomp.c counter.c fsm.c \
 			 write_queue.c utils.c socket.c \
 			 logging.c logging_syslog.c logging_gsmtap.c rate_ctr.c \