More SIGQUIT handling, various Thread fixes.

Change-Id: I3233c300d1c838c2eee0ba9be6018b7fbd907386
diff --git a/src/check_jni.cc b/src/check_jni.cc
index 8a30279..dc58565 100644
--- a/src/check_jni.cc
+++ b/src/check_jni.cc
@@ -917,7 +917,7 @@
    * to "running" mode before doing the checks.
    */
   void checkInstance(InstanceKind kind, jobject java_object) {
-    const char* what;
+    const char* what = NULL;
     switch (kind) {
     case kClass:
       what = "jclass";