Don't enable leak detector if NDEBUG is defined

Signed-off-by: falkTX <falktx@falktx.com>

distrho/extra/LeakDetector.hpp

@@ -50,7 +50,7 @@ START_NAMESPACE_DISTRHO
 #define DISTRHO_JOIN_MACRO_HELPER(a, b) a ## b
 #define DISTRHO_JOIN_MACRO(item1, item2) DISTRHO_JOIN_MACRO_HELPER(item1, item2)
 
-#ifdef DEBUG
+#if defined(DEBUG) && !defined(NDEBUG)
 /** This macro lets you embed a leak-detecting object inside a class.\n
     To use it, simply declare a DISTRHO_LEAK_DETECTOR(YourClassName) inside a private section
     of the class declaration. E.g.