Add #include <array> to fix compile error

gcc complains std::array being undeclared when trying to build a fresh
clone.

sim/simx/tex_unit.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <array>
 #include "types.h"
 
 namespace vortex {
@@ -25,4 +26,4 @@ private:
     Core* core_;
 };
 
-}
+}