Resolve various "no previous declaration" warnings

Source/Core/Common/Debug/CodeTrace.cpp

@@ -48,6 +48,21 @@ u32 GetMemoryTargetSize(std::string_view instr)
 
   return 4;
 }
+
+bool CompareMemoryTargetToTracked(const std::string& instr, const u32 mem_target,
+                                  const std::set<u32>& mem_tracked)
+{
+  // This function is hit often and should be optimized.
+  auto it_lower = std::lower_bound(mem_tracked.begin(), mem_tracked.end(), mem_target);
+
+  if (it_lower == mem_tracked.end())
+    return false;
+  else if (*it_lower == mem_target)
+    return true;
+
+  // If the base value doesn't hit, still need to check if longer values overlap.
+  return *it_lower < mem_target + GetMemoryTargetSize(instr);
+}
 }  // namespace
 
 void CodeTrace::SetRegTracked(const std::string& reg)
@@ -124,21 +139,6 @@ TraceOutput CodeTrace::SaveCurrentInstruction() const
   return output;
 }
 
-bool CompareMemoryTargetToTracked(const std::string& instr, const u32 mem_target,
-                                  const std::set<u32>& mem_tracked)
-{
-  // This function is hit often and should be optimized.
-  auto it_lower = std::lower_bound(mem_tracked.begin(), mem_tracked.end(), mem_target);
-
-  if (it_lower == mem_tracked.end())
-    return false;
-  else if (*it_lower == mem_target)
-    return true;
-
-  // If the base value doesn't hit, still need to check if longer values overlap.
-  return *it_lower < mem_target + GetMemoryTargetSize(instr);
-}
-
 AutoStepResults CodeTrace::AutoStepping(bool continue_previous, AutoStop stop_on)
 {
   AutoStepResults results;

Source/Core/Common/FatFsUtil.cpp

@@ -195,6 +195,7 @@ extern "C" DWORD get_fattime(void)
   return static_cast<DWORD>(s_callbacks->GetCurrentTimeFAT());
 }
 
+#if FF_USE_LFN == 3  // match ff.h; currently unused by Dolphin
 extern "C" void* ff_memalloc(UINT msize)
 {
   return std::malloc(msize);
@@ -204,7 +205,9 @@ extern "C" void ff_memfree(void* mblock)
 {
   return std::free(mblock);
 }
+#endif
 
+#if FF_FS_REENTRANT
 extern "C" int ff_cre_syncobj(BYTE vol, FF_SYNC_t* sobj)
 {
   *sobj = new std::recursive_mutex();
@@ -229,6 +232,7 @@ extern "C" int ff_del_syncobj(FF_SYNC_t sobj)
   delete reinterpret_cast<std::recursive_mutex*>(sobj);
   return 1;
 }
+#endif
 
 static const char* FatFsErrorToString(FRESULT error_code)
 {

Source/Core/Core/IOS/USB/Emulated/Skylander.cpp

@@ -1144,9 +1144,9 @@ void SkylanderPortal::WriteBlock(u8 sky_num, u8 block, const u8* to_write_buf, u
   }
 }
 
-u16 SkylanderCRC16(u16 init_value, const u8* buffer, u32 size)
+static u16 SkylanderCRC16(u16 init_value, const u8* buffer, u32 size)
 {
-  const unsigned short CRC_CCITT_TABLE[256] = {
+  static constexpr std::array<u16, 256> CRC_CCITT_TABLE{
       0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A,
       0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294,
       0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462,

Source/Core/InputCommon/GCAdapter.cpp

@@ -752,7 +752,7 @@ GCPadStatus Input(int chan)
 }
 
 // Get ControllerType from first byte in input payload.
-ControllerType IdentifyControllerType(u8 data)
+static ControllerType IdentifyControllerType(u8 data)
 {
   if (Common::ExtractBit<4>(data))
     return ControllerType::Wired;