Fix OSX and Windows build

dgl/Makefile

@@ -43,6 +43,7 @@ all: $(TARGET)
 	$(AR) crs $@ $^
 
 ../libdgl.dll: $(OBJS)
+	# -Wl,--output-def,$@.def,--out-implib,$@.a
 	$(CXX) $^ -shared $(LINK_FLAGS) -o $@
 
 ../libdgl.dylib: $(OBJS)
@@ -56,6 +57,9 @@ all: $(TARGET)
 %.cpp.o: %.cpp
 	$(CXX) $< $(BUILD_CXX_FLAGS) -c -o $@
 
+%.m.o: %.m
+	$(CC) $< $(BUILD_C_FLAGS) -objc -c -o $@
+
 # --------------------------------------------------------------
 
 clean:

dgl/src/Window.cpp

@@ -436,7 +436,7 @@ public:
 
 #if DGL_OS_WINDOWS
         // Center this window
-        PuglInternals* const parentImpl = fParent->fView->impl;
+        PuglInternals* const parentImpl = fModal.parent->fView->impl;
 
         RECT curRect;
         RECT parentRect;