More SIGQUIT handling, various Thread fixes.

Change-Id: I3233c300d1c838c2eee0ba9be6018b7fbd907386
diff --git a/src/utils.h b/src/utils.h
index 3a6f404..4c2a7f9 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -168,7 +168,7 @@
 // Returns the JNI native function name for the overloaded method 'm'.
 std::string JniLongName(const Method* m);
 
-std::string ReadFileToString(const char* file_name);
+bool ReadFileToString(const std::string& file_name, std::string* result);
 
 // Returns the current date in ISO yyyy-mm-dd hh:mm:ss format.
 std::string GetIsoDate();