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/src/java_lang_Runtime.cc b/src/java_lang_Runtime.cc
index a057d36..44703b7 100644
--- a/src/java_lang_Runtime.cc
+++ b/src/java_lang_Runtime.cc
@@ -32,7 +32,7 @@
   Runtime::Current()->GetHeap()->CollectGarbage(false);
 }
 
-static void Runtime_nativeExit(JNIEnv* env, jclass, jint status, jboolean isExit) {
+static void Runtime_nativeExit(JNIEnv*, jclass, jint status, jboolean isExit) {
   // isExit is true for System.exit and false for System.halt.
   if (isExit) {
     Runtime::Current()->CallExitHook(status);
@@ -64,15 +64,15 @@
   return env->NewStringUTF(detail.c_str());
 }
 
-static jlong Runtime_maxMemory(JNIEnv* env, jclass) {
+static jlong Runtime_maxMemory(JNIEnv*, jclass) {
   return Runtime::Current()->GetHeap()->GetMaxMemory();
 }
 
-static jlong Runtime_totalMemory(JNIEnv* env, jclass) {
+static jlong Runtime_totalMemory(JNIEnv*, jclass) {
   return Runtime::Current()->GetHeap()->GetTotalMemory();
 }
 
-static jlong Runtime_freeMemory(JNIEnv* env, jclass) {
+static jlong Runtime_freeMemory(JNIEnv*, jclass) {
   return Runtime::Current()->GetHeap()->GetFreeMemory();
 }