Clang: Fix errors when building with clang on windows with C++20 enabled

modules/juce_dsp/widgets/juce_WaveShaper.h

@@ -66,7 +66,7 @@ struct WaveShaper
 //==============================================================================
 // Although clang supports C++17, their standard library still has no invoke_result
 // support. Remove the "|| JUCE_CLANG" once clang supports this properly!
-#if (! JUCE_CXX17_IS_AVAILABLE) || JUCE_CLANG
+#if (! JUCE_CXX17_IS_AVAILABLE) || (JUCE_CLANG && ! JUCE_WINDOWS)
 template <typename Functor>
 static WaveShaper<typename std::result_of<Functor>, Functor> CreateWaveShaper (Functor functionToUse)   { return {functionToUse}; }
 #else

modules/juce_graphics/geometry/juce_PathIterator.cpp

@@ -64,7 +64,7 @@ bool PathFlatteningIterator::next()
     {
         float type;
 
-        if (stackPos == stackBase)
+        if (stackPos == stackBase.get())
         {
             if (source == path.data.end())
                 return false;
@@ -129,7 +129,7 @@ bool PathFlatteningIterator::next()
         {
             ++subPathIndex;
 
-            closesSubPath = stackPos == stackBase
+            closesSubPath = stackPos == stackBase.get()
                              && source != path.data.end()
                              && *source == Path::closeSubPathMarker
                              && x2 == subPathCloseX