drop -lrt linkage

With glibc-2.19, the clock symbols are in libc, so we don't have to
link in librt anymore.

BUG=None
TEST=`FEATURES=test emerge-link audiotest` still works

Change-Id: Ic5403cee6619541d81f12e84453db3ac818c7225
Reviewed-on: https://chromium-review.googlesource.com/216864
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/Makefile b/Makefile
index 9a2a890..b4a6851 100644
--- a/Makefile
+++ b/Makefile
@@ -44,7 +44,7 @@
 CC_BINARY(looptest): \
 	CFLAGS += $(ALSA_CFLAGS)
 CC_BINARY(looptest): \
-	LDLIBS += $(ALSA_LIBS) -lrt
+	LDLIBS += $(ALSA_LIBS)
 clean: CLEAN(looptest)
 all: CC_BINARY(looptest)
 
@@ -54,6 +54,6 @@
 CC_BINARY(loopback_latency): \
 	CFLAGS += $(ALSA_CFLAGS) $(CRAS_CFLAGS)
 CC_BINARY(loopback_latency): \
-	LDLIBS += $(ALSA_LIBS) $(CRAS_LIBS) -lrt
+	LDLIBS += $(ALSA_LIBS) $(CRAS_LIBS)
 clean: CC_BINARY(loopback_latency)
 all: CC_BINARY(loopback_latency)