include <algorithm> to fix Windows build

src/effects/Effect.cpp

@@ -24,6 +24,8 @@ greater use in future.
 #include "../Audacity.h"
 #include "Effect.h"
 
+#include <algorithm>
+
 #include <wx/defs.h>
 #include <wx/hashmap.h>
 #include <wx/msgdlg.h>

src/effects/Paulstretch.cpp

@@ -17,6 +17,8 @@
 #include "../Audacity.h"
 #include "Paulstretch.h"
 
+#include <algorithm>
+
 #include <math.h>
 #include <float.h>
 

src/effects/TruncSilence.cpp

@@ -18,6 +18,8 @@
 #include "../Audacity.h"
 #include "TruncSilence.h"
 
+#include <algorithm>
+
 #include <limits>
 #include <math.h>
 

src/effects/nyquist/Nyquist.cpp

@@ -26,6 +26,8 @@ effects from this one class.
 
 #include "../../Audacity.h"
 
+#include <algorithm>
+
 #include <math.h>
 #include <locale.h>