[Platform] [x86 Real Mode] Implement Turbo C++ 4.0J exception handler removal

Full version with support for `operator new`.

Part of P0230, funded by [Anonymous].

platform/x86real/noexcept.cpp

@@ -0,0 +1,50 @@
+// Remove C++ exception handler bloat on Borland compilers
+// (see https://community.embarcadero.com/article/technical-articles/162/14700)
+// ----------------------------------------------------------------------------
+
+#pragma option -zC_TEXT
+
+#if defined(__TURBOC__) && defined(__MSDOS__)
+
+#include <malloc.h>
+#include <new.h>
+#include "platform.h"
+
+extern "C" void __cdecl _ExceptInit(void)
+{
+}
+
+new_handler _new_handler = nullptr;
+
+new_handler __cdecl set_new_handler(new_handler p)
+{
+	new_handler t = _new_handler;
+	_new_handler = p;
+	return t;
+}
+
+void* __cdecl operator new(size_t size)
+{
+	void* p = nullptr;
+	if(size == 0) {
+		size = 1;
+	}
+	while(((p = malloc(size)) == nullptr) && (_new_handler != nullptr)) {
+		_new_handler();
+	}
+	return p;
+}
+
+void far* __cdecl operator new(uint32_t size)
+{
+	void far* p = nullptr;
+	if(size == 0) {
+		size = 1;
+	}
+	while(((p = farmalloc(size)) == nullptr) && (_new_handler != nullptr)) {
+		_new_handler();
+	}
+	return p;
+}
+
+#endif