liblog: set -Werror

- Deal with some -Wunused issues
- Cleanup UNUSED to __unused transition

Change-Id: Icd33808d4c974625f4fd0a126a90a2b4c90c8314
diff --git a/liblog/tests/liblog_benchmark.cpp b/liblog/tests/liblog_benchmark.cpp
index 39fe2ad..549d79e 100644
--- a/liblog/tests/liblog_benchmark.cpp
+++ b/liblog/tests/liblog_benchmark.cpp
@@ -99,7 +99,7 @@
 }
 BENCHMARK(BM_log_overhead);
 
-static void caught_latency(int signum)
+static void caught_latency(int /*signum*/)
 {
     unsigned long long v = 0xDEADBEEFA55A5AA5ULL;
 
@@ -193,7 +193,7 @@
 }
 BENCHMARK(BM_log_latency);
 
-static void caught_delay(int signum)
+static void caught_delay(int /*signum*/)
 {
     unsigned long long v = 0xDEADBEEFA55A5AA6ULL;