Fix all our unused parameter warnings so we let GCC report them.

There were a couple of genuine bugs here (fixed), plus there's a missing
feature in trace.cc that I've just added a TODO for.

Also note that I haven't touched the compilers; this warning is still
explicitly disabled for that code. I'll do that when there's less going
on in those directories.

Change-Id: Ic3570bf82411a07c7530bfaf1995ac995b9fc00f
diff --git a/test/StackWalk/stack_walk_jni.cc b/test/StackWalk/stack_walk_jni.cc
index 65b3284..95f3807 100644
--- a/test/StackWalk/stack_walk_jni.cc
+++ b/test/StackWalk/stack_walk_jni.cc
@@ -94,8 +94,7 @@
   }
 };
 
-extern "C"
-JNIEXPORT jint JNICALL Java_StackWalk_refmap(JNIEnv* env, jobject thisObj, jint count) {
+extern "C" JNIEXPORT jint JNICALL Java_StackWalk_refmap(JNIEnv*, jobject, jint count) {
   CHECK_EQ(count, 0);
   gJava_StackWalk_refmap_calls++;
 
@@ -106,8 +105,7 @@
   return count + 1;
 }
 
-extern "C"
-JNIEXPORT jint JNICALL Java_StackWalk2_refmap2(JNIEnv* env, jobject thisObj, jint count) {
+extern "C" JNIEXPORT jint JNICALL Java_StackWalk2_refmap2(JNIEnv*, jobject, jint count) {
   gJava_StackWalk_refmap_calls++;
 
   // Visitor