jvmti-int.h (JVMTI): Declare member "enabled".

* include/jvmti-int.h (JVMTI): Declare member "enabled".
        * jvmti.cc (JVMTI): Add member "enabled".
        (_Jv_GetJVMTIEnv): Mark JVMTI enabled.
        * interpret.cc (_Jv_InterpMethod::ncode): Use JVMTI::enabled
        instead of gnu::classpath::jdwp::Jdwp::isDebugging.
        (_Jv_CompileMethod): If JVMTI is enabled, use run_debug
        instead of run to compile the method.

        * interpret-run.cc [DEBUG] (NEXT_INSN): Add JVMTI single step
        notification.

From-SVN: r121442

libjava/include/jvmti-int.h

@@ -37,6 +37,10 @@ executable file might be covered by the GNU General Public License. */
    False means no JVMTI environment requested that event type. */
 namespace JVMTI
 {
+  // Is JVMTI enabled? (i.e., any jvmtiEnv created?)
+  extern bool enabled;
+
+  // Event notifications
   extern bool VMInit;
   extern bool VMDeath;
   extern bool ThreadStart;