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/dalvik_system_VMRuntime.cc b/src/dalvik_system_VMRuntime.cc
index 3799bcf..ef11f4b 100644
--- a/src/dalvik_system_VMRuntime.cc
+++ b/src/dalvik_system_VMRuntime.cc
@@ -129,7 +129,7 @@
   t->GetJniEnv()->SetCheckJniEnabled(false);
 }
 
-static void VMRuntime_setTargetSdkVersion(JNIEnv* env, jobject, jint targetSdkVersion) {
+static void VMRuntime_setTargetSdkVersion(JNIEnv*, jobject, jint targetSdkVersion) {
   // This is the target SDK version of the app we're about to run.
   // Note that targetSdkVersion may be CUR_DEVELOPMENT (10000).
   // Note that targetSdkVersion may be 0, meaning "current".
@@ -150,7 +150,7 @@
   }
 }
 
-static void VMRuntime_trimHeap(JNIEnv* env, jobject) {
+static void VMRuntime_trimHeap(JNIEnv*, jobject) {
   ScopedHeapLock heap_lock;
   Heap* heap = Runtime::Current()->GetHeap();
   size_t alloc_space_size = heap->GetAllocSpace()->Size();