Fix more gcc compilation issues

src/ZoneLoading/Loading/Steps/StepVerifyHash.cpp

@@ -1,6 +1,7 @@
 #include "StepVerifyHash.h"
 
 #include <memory>
+#include <cstring>
 
 #include "Loading/Exception/InvalidHashException.h"
 

src/ZoneLoading/Loading/Steps/StepVerifyMagic.cpp

@@ -1,17 +1,20 @@
 #include "StepVerifyMagic.h"
+
+#include <cstring>
+
 #include "Loading/Exception/InvalidMagicException.h"
 
 StepVerifyMagic::StepVerifyMagic(const char* magic)
 {
     m_magic = magic;
+    m_magic_len = strlen(m_magic);
 }
 
 void StepVerifyMagic::PerformStep(ZoneLoader* zoneLoader, ILoadingStream* stream)
 {
-    const size_t magicLength = strlen(m_magic);
     char currentCharacter;
 
-    for(unsigned i = 0; i < magicLength; i++)
+    for(unsigned i = 0; i < m_magic_len; i++)
     {
         stream->Load(&currentCharacter, sizeof(char));
 

src/ZoneLoading/Loading/Steps/StepVerifyMagic.h

@@ -5,6 +5,7 @@
 class StepVerifyMagic final : public ILoadingStep
 {
     const char* m_magic;
+    size_t m_magic_len;
 
 public:
     explicit StepVerifyMagic(const char* magic);