Add missing stddef header where size_t is used.

Inputs/Joystick.hpp

@@ -9,6 +9,7 @@
 #ifndef Joystick_hpp
 #define Joystick_hpp
 
+#include <cstddef>
 #include <vector>
 
 namespace Inputs {

Inputs/Keyboard.cpp

@@ -8,6 +8,8 @@
 
 #include "Keyboard.hpp"
 
+#include <cstddef>
+
 using namespace Inputs;
 
 Keyboard::Keyboard(const std::set<Key> &essential_modifiers) : essential_modifiers_(essential_modifiers) {

Machines/Utility/MemoryPacker.cpp

@@ -8,6 +8,8 @@
 
 #include "MemoryPacker.hpp"
 
+#include <cstddef>
+
 void Memory::PackBigEndian16(const std::vector<uint8_t> &source, uint16_t *target) {
 	for(size_t c = 0; c < source.size(); c += 2) {
 		target[c >> 1] = uint16_t(source[c] << 8) | uint16_t(source[c+1]);

Processors/65816/65816.hpp

@@ -10,6 +10,7 @@
 #define WDC65816_hpp
 
 #include <cassert>
+#include <cstddef>
 #include <cstdint>
 #include <vector>
 

SignalProcessing/FIRFilter.cpp

@@ -7,7 +7,9 @@
 //
 
 #include "FIRFilter.hpp"
+
 #include <cmath>
+#include <cstddef>
 
 #ifndef M_PI
 #define M_PI 3.1415926f