diff --git a/sys/platform.h b/sys/platform.h
index d9a9a5b..1beb68b 100644
--- a/sys/platform.h
+++ b/sys/platform.h
@@ -32,6 +32,16 @@ If you have questions concerning this license or the applicable additional terms
 #include "config.h"
 #include "framework/BuildDefines.h"
 
+#ifdef _WIN32
+#include <malloc.h> // _alloca()
+#endif
+
+// NOTE: By default Win32 uses a 1MB stack. Doom3 1.3.1 uses 4MB (probably set after compiling with EDITBIN /STACK
+// dhewm3 now uses a 8MB stack, set with a linker flag in CMakeLists.txt (/STACK:8388608 for MSVC, -Wl,--stack,8388608 for mingw)
+// Linux has a 8MB stack by default, and so does macOS, at least for the main thread
+// anyway, a 2MB limit alloca should be safe even when using it multiple times in the same function
+#define ID_MAX_ALLOCA_SIZE 2097152 // 2MB
+
 /*
 ===============================================================================
 
@@ -40,7 +50,7 @@ If you have questions concerning this license or the applicable additional terms
 ===============================================================================
 */
 
-// Win32
+// AROS
 #if defined(__AROS__)
 
 #define _alloca						alloca
@@ -71,7 +81,14 @@ If you have questions concerning this license or the applicable additional terms
 // Win32
 #if defined(WIN32) || defined(_WIN32)
 
-#define _alloca16( x )				((void *)((((uintptr_t)_alloca( (x)+15 )) + 15) & ~15))
+#ifdef __MINGW32__
+  #undef _alloca // in mingw _alloca is a #define
+  #define _alloca16( x )			( (assert((x)<ID_MAX_ALLOCA_SIZE)), __builtin_alloca_with_align( (x), 16*8 ) )
+  #define _alloca( x )				( (assert((x)<ID_MAX_ALLOCA_SIZE)), __builtin_alloca( (x) ) )
+#else
+  #define _alloca16( x )			( (void *) ( (assert((x)<ID_MAX_ALLOCA_SIZE)), ((((uintptr_t)_alloca( (x)+15 )) + 15) & ~15) ) )
+  #define _alloca( x )				( (void *) ( (assert((x)<ID_MAX_ALLOCA_SIZE)), _alloca( (x) ) ) )
+#endif
 
 #define PATHSEPERATOR_STR			"\\"
 #define PATHSEPERATOR_CHAR			'\\'
@@ -105,6 +122,35 @@ If you have questions concerning this license or the applicable additional terms
 
 #endif
 
+// Setting D3_ARCH for VisualC++ from CMake doesn't work when using VS integrated CMake
+// so set it in code instead
+#ifdef _MSC_VER
+
+#ifdef D3_ARCH
+  #undef D3_ARCH
+#endif // D3_ARCH
+
+#ifdef _M_X64
+  // this matches AMD64 and ARM64EC (but not regular ARM64), but they're supposed to be binary-compatible somehow, so whatever
+  #define D3_ARCH "x86_64"
+#elif defined(_M_ARM64)
+  #define D3_ARCH "arm64"
+#elif defined(_M_ARM)
+  #define D3_ARCH "arm"
+#elif defined(_M_IX86)
+  #define D3_ARCH "x86"
+#else
+  // if you're not targeting one of the aforementioned architectures,
+  // check https://learn.microsoft.com/en-us/cpp/preprocessor/predefined-macros
+  // to find out how to detect yours and add it here - and please send a patch :)
+  #error "Unknown CPU architecture!"
+  // (for a quick and dirty solution, comment out the previous line, but keep in mind
+  //  that savegames may not be compatible with other builds of dhewm3)
+  #define D3_ARCH "UNKNOWN"
+#endif // _M_X64 etc
+
+#endif // _MSC_VER
+
 
 // Mac OSX
 #if defined(MACOS_X) || defined(__APPLE__)
@@ -139,8 +185,15 @@ If you have questions concerning this license or the applicable additional terms
 // Unix
 #ifdef __unix__
 
-#define _alloca						alloca
-#define _alloca16( x )				((void *)((((uintptr_t)alloca( (x)+15 )) + 15) & ~15))
+#if !defined(__GNUC__) || (defined(__MCST__) && __LCC__ < 128)
+  // MCST-LCC < 1.28 does not support __builtin_alloca_with_align()
+  #define _alloca( x )				(({assert( (x)<ID_MAX_ALLOCA_SIZE );}), alloca( (x) ))
+  #define _alloca16( x )			(({assert( (x)<ID_MAX_ALLOCA_SIZE );}),((void *)((((uintptr_t)alloca( (x)+15 )) + 15) & ~15)))
+#else
+  // GCC, CLANG, MCST-LCC >= 1.28
+  #define _alloca16( x )			( ({assert((x)<ID_MAX_ALLOCA_SIZE);}), __builtin_alloca_with_align( (x), 16*8 ) )
+  #define _alloca( x )				( ({assert((x)<ID_MAX_ALLOCA_SIZE);}), __builtin_alloca( (x) ) )
+#endif
 
 #ifdef GAME_DLL
 #define ID_GAME_API					__attribute__((visibility ("default")))
@@ -179,9 +232,6 @@ If you have questions concerning this license or the applicable additional terms
 	// MSVC does not provide this C99 header
 	#include <inttypes.h>
 #endif
-#if defined(__MINGW32__)
-	#include <malloc.h>
-#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -200,6 +250,18 @@ If you have questions concerning this license or the applicable additional terms
 #undef FindText								// stupid namespace poluting Microsoft monkeys
 #endif
 
+// Apple legacy
+#ifdef __APPLE__
+#include <Availability.h>
+#ifdef __MAC_OS_X_VERSION_MIN_REQUIRED
+#if __MAC_OS_X_VERSION_MIN_REQUIRED == 1040
+#define OSX_TIGER
+#elif __MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+#define OSX_LEOPARD
+#endif
+#endif
+#endif
+
 #define ID_TIME_T time_t
 
 typedef unsigned char			byte;		// 8 bits