Params: added pthread.h include to fix compile

Added #include <pthread.h> in PADnoteParameters.h to fix windows compile error
Patch by: Tobias Doerffel
(cherry picked from commit 14d2751bed1e6bb11805bb17e4a73e622c85a4ac)

plugins/zynaddsubfx/AUTHORS.txt

@@ -13,6 +13,6 @@ Contributors:
         Achim Settelmeier (QUERTZ keyboard layout for virtual keyboard)
         J<>r<EFBFBD>mie Andr<64>i (AZERTY keyboard layout, Array index fix, OSS failsafe)
         Alexis Ballier (const char* <-> string mismatch, NULLMidi prototype fix)
-        Tobias Doerffel (static vs instance variables alteration)
+        Tobias Doerffel (static-instance variables fix, missing include fix)
         James Morris (Memory leaks in FLTK GUI)
 

plugins/zynaddsubfx/src/Params/PADnoteParameters.h

@@ -35,6 +35,7 @@
 #include "FilterParams.h"
 #include "Presets.h"
 #include <string>
+#include <pthread.h>
 
 class PADnoteParameters:public Presets
 {