Use -Werror in system/extras

* Remove unused variables.
* Fix redefined macro warnings.
* Fix sign-compare warnings.
* Fix 'return false' in main().
* Keep existing warnings to fix later.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Ib92ef5297693595fb84ed4f8e61665bda4cee312
diff --git a/crypto-perf/crypto.cpp b/crypto-perf/crypto.cpp
index 2cd2709..c186076 100644
--- a/crypto-perf/crypto.cpp
+++ b/crypto-perf/crypto.cpp
@@ -121,7 +121,7 @@
     CPU_SET(cmd_data.cpu_to_lock, &cpuset);
     if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
 	perror("sched_setaffinity failed");
-	return false;
+	return 1;
     }
     gettimeofday(&begin_time, NULL);
     while (count < MAX_COUNT) {