Multiinstance jit (#2201)

* works on Linux x64
still needs to be fixed for everything else

* use lots of PROT_NONE memory to reliably reserve virtual address space

* multi instance fastmem on Linux

* Windows

* blarg

* disable fastmem if the page size is not 4kb

* fix fast mem dialog option

* make aarch64 work as well

* fastmem 16kb pages support

src/ARMJIT_Global.h

@@ -0,0 +1,44 @@
+/*
+    Copyright 2016-2024 melonDS team
+
+    This file is part of melonDS.
+
+    melonDS is free software: you can redistribute it and/or modify it under
+    the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
+    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with melonDS. If not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef ARMJIT_GLOBAL_H
+#define ARMJIT_GLOBAL_H
+
+#include "types.h"
+
+#include <stdlib.h>
+
+namespace melonDS
+{
+
+namespace ARMJIT_Global
+{
+
+static constexpr size_t CodeMemorySliceSize = 1024*1024*32;
+
+void Init();
+void DeInit();
+
+void* AllocateCodeMem();
+void FreeCodeMem(void* codeMem);
+
+}
+
+}
+
+#endif