Assorted portability enhancements (#1800)

* Introduce some Platform calls for managing dynamic libraries

* Add Platform::WriteFATSectors

* Introduce some Platform calls for managing dynamic libraries

* Add Platform::WriteFATSectors

* Change includes of "../types.h" to "types.h"

- Makes it easier to directly include these headers in downstream projects

* Change an include of "../Wifi.h" to "Wifi.h"

* Allow CommonFuncs.cpp to compile on Android

* Tidy up some logging calls

- Use Platform::Log in LAN_Socket.cpp
- Soften some warnings to Debug logs (since they don't necessarily represent problems)

* Add Platform::EnterGBAMode

- Gracefully stop the emulator if trying to enter GBA mode

* Soften some logs that most players won't care about

* Soften some more logs

* Introduce Platform wrappers for file operations

* Fix pointer spacing

* Fix more style nits

* Log the errno when ftruncate fails

* Fix FileSeek offset argument

- With an s32 offset, we couldn't access files larger than 2GB

* Revise Platform::StopEmu to address feedback

- Remove Platform::EnterGBAMode in favor of adding a reason to Platform::StopEmu
- Also rename Platform::StopEmu to Platform::SignalStop
- Add an optional argument to NDS::Stop
- Use the new argument everywhere that the console stops itself

* Rename FileGetString to FileReadLine

- It conveys the meaning better

* Rename FileSeekOrigin::Set to Start

- It conveys the meaning better

* Change definition of FileGetString to FileReadLine

- Oops, almost forgot it

* Rename FlushFile to FileFlush

- To remain consistent with the other File functions

* Add a FileType usage

* Fix line break in FileSeekOrigin

* Document Platform::DeInit

* Clarify that StopReason::Unknown doesn't always mean an error

* Move and document FileType::HostFile

* Remove Platform::OpenDataFile

- Nothing currently uses it

* Refactor Platform::OpenFile and Platform::OpenLocalFile to accept a FileMode enum instead of a string

- The enum is converted to fopen flags under the hood
- The file type is used to decide whether to add the "b" flag
- Some helper functions are exposed for the benefit of consistent behavior among frontends
- Equivalent behavior is maintained

* Fix a tab that should be spaces

* Use Windows' 64-bit implementations of fseek/ftell

* Move Platform::IsBinaryFile to Platform.cpp

- It could vary by frontend

* Remove an unused FileType

* Rename an enum constant

* Document various Platform items

* Use Platform::DynamicLibrary to load libandroid

- And clean it up at the end

* Fix a typo

* Pass the correct filetype to FATStorage

- Since it can be used for DSI NAND images or for SD cards

* Remove Platform::FileType

src/GPU3D.cpp

@@ -2727,7 +2727,7 @@ u8 Read8(u32 addr)
         }
     }
 
-    Log(LogLevel::Warn, "unknown GPU3D read8 %08X\n", addr);
+    Log(LogLevel::Debug, "unknown GPU3D read8 %08X\n", addr);
     return 0;
 }
 
@@ -2771,7 +2771,7 @@ u16 Read16(u32 addr)
     case 0x04000634: return VecTestResult[2];
     }
 
-    Log(LogLevel::Warn, "unknown GPU3D read16 %08X\n", addr);
+    Log(LogLevel::Debug, "unknown GPU3D read16 %08X\n", addr);
     return 0;
 }
 
@@ -2875,7 +2875,7 @@ void Write8(u32 addr, u8 val)
         return;
     }
 
-    Log(LogLevel::Warn, "unknown GPU3D write8 %08X %02X\n", addr, val);
+    Log(LogLevel::Debug, "unknown GPU3D write8 %08X %02X\n", addr, val);
 }
 
 void Write16(u32 addr, u16 val)
@@ -2962,7 +2962,7 @@ void Write16(u32 addr, u16 val)
         return;
     }
 
-    Log(LogLevel::Warn, "unknown GPU3D write16 %08X %04X\n", addr, val);
+    Log(LogLevel::Debug, "unknown GPU3D write16 %08X %04X\n", addr, val);
 }
 
 void Write32(u32 addr, u32 val)
@@ -3059,7 +3059,7 @@ void Write32(u32 addr, u32 val)
         return;
     }
 
-    Log(LogLevel::Warn, "unknown GPU3D write32 %08X %08X\n", addr, val);
+    Log(LogLevel::Debug, "unknown GPU3D write32 %08X %08X\n", addr, val);
 }
 
 Renderer3D::Renderer3D(bool Accelerated)