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/DSi_SD.cpp

@@ -23,8 +23,7 @@
 #include "DSi_NWifi.h"
 #include "Platform.h"
 
-using Platform::Log;
-using Platform::LogLevel;
+using namespace Platform;
 
 // observed IRQ behavior during transfers
 //
@@ -773,7 +772,7 @@ DSi_MMCStorage::DSi_MMCStorage(DSi_SDHost* host, bool internal, const std::strin
     : DSi_SDDevice(host)
 {
     Internal = internal;
-    File = Platform::OpenLocalFile(filename, "r+b");
+    File = Platform::OpenLocalFile(filename, FileMode::ReadWriteExisting);
 
     SD = nullptr;
 
@@ -801,7 +800,7 @@ DSi_MMCStorage::~DSi_MMCStorage()
     }
     if (File)
     {
-        fclose(File);
+        CloseFile(File);
     }
 }
 
@@ -926,7 +925,7 @@ void DSi_MMCStorage::SendCMD(u8 cmd, u32 param)
 
     case 12: // stop operation
         SetState(0x04);
-        if (File) fflush(File);
+        if (File) FileFlush(File);
         RWCommand = 0;
         Host->SendResponse(CSR, true);
         return;
@@ -1055,8 +1054,8 @@ u32 DSi_MMCStorage::ReadBlock(u64 addr)
     }
     else if (File)
     {
-        fseek(File, addr, SEEK_SET);
-        fread(&data[addr & 0x1FF], 1, len, File);
+        FileSeek(File, addr, FileSeekOrigin::Start);
+        FileRead(&data[addr & 0x1FF], 1, len, File);
     }
 
     return Host->DataRX(&data[addr & 0x1FF], len);
@@ -1085,8 +1084,8 @@ u32 DSi_MMCStorage::WriteBlock(u64 addr)
             }
             else if (File)
             {
-                fseek(File, addr, SEEK_SET);
-                fwrite(&data[addr & 0x1FF], 1, len, File);
+                FileSeek(File, addr, FileSeekOrigin::Start);
+                FileWrite(&data[addr & 0x1FF], 1, len, File);
             }
         }
     }