Only apply Asyncify to functions that really need it

This creates asyncify.txt from emterpretify.txt, with functions
in the different format needed by ASYNCIFY_ONLY. It leads to a
bunch of these warnings, because some functions get inlined:
warning: Asyncify onlylist contained a non-matching pattern:
That is okay and apparently unavoidable. The important thing is
that no such warnings occur when the final link is done using -O0.

ASYNCIFY_ADVISE has shown that a lot more would be processed by
Asyncify without this. The performance penalty isn't too bad, and
is much better than the Emterpreter. Maybe more extensive use of
Asyncify could make more things work, but taking advantage of that
would require code changes.

src/Makefile.am

@@ -28,7 +28,8 @@ else
 # It is only required when using emterpreter.
 dosbox_LDFLAGS+=--memory-init-file 0
 if ASYNCIFY
-dosbox_LDFLAGS+=-s ASYNCIFY=1 -s FETCH=1
+dosbox_LDFLAGS+=-s ASYNCIFY=1 -s FETCH=1 -s [email protected]
+EXTRA_dosbox_DEPENDENCIES=asyncify.txt
 endif
 endif
 if WEBASSEMBLY

src/asyncify.txt

@@ -0,0 +1,48 @@
+[
+"main",
+"SHELL_Init()",
+"DOS_ReadFile(unsigned short, unsigned char*, unsigned short*, bool)",
+"DOSBOX_RunMachine()",
+"CALLBACK_RunRealInt(unsigned char)",
+"CALLBACK_RunRealFar(unsigned short, unsigned short)",
+"CALLBACK_Idle()",
+"Normal_Loop()",
+"DOS_21Handler()",
+"PROGRAMS_Handler()",
+"device_CON::Read(unsigned char*, unsigned short*)",
+"device_CON::device_CON()",
+"DOS_Device::Read(unsigned char*, unsigned short*)",
+"MEM::Run()",
+"INTRO::Run()",
+"BOOT::Run()",
+"Config::StartUp()",
+"Config::Init()",
+"Section::ExecuteInit(bool)",
+"GUI_StartUp(Section*)",
+"DOS_Shell::InputCommand(char*)",
+"DOS_Shell::Run()",
+"DOS_Shell::Execute(char*, char*)",
+"DOS_Shell::DoCommand(char*)",
+"DOS_Shell::ParseLine(char*)",
+"DOS_Shell::CMD_HELP(char*)",
+"DOS_Shell::CMD_PAUSE(char*)",
+"DOS_Shell::CMD_CHOICE(char*)",
+"DOS_Shell::CMD_DIR(char*)",
+"DOS_Shell::CMD_TIME(char*)",
+"DOS_Shell::CMD_CLS(char*)",
+"DOS_Shell::CMD_DATE(char*)",
+"DOS_Shell::CMD_COPY(char*)",
+"Reboot_Handler()",
+"DOS_LoadKeyboardLayout(char const*, int, char const*)",
+"DOS_KeyboardLayout_Init(Section*)",
+"DOS_SwitchKeyboardLayout(char const*, int&)",
+"keyboard_layout::read_codepage_file(char const*, int)",
+"keyboard_layout::switch_keyboard_layout(char const*, keyboard_layout*&, int&)",
+"DOS_KeyboardLayout::DOS_KeyboardLayout(Section*)",
+"KEYB::Run()",
+"PIC_RunQueue()",
+"MAPPER_RunEvent(unsigned int)",
+"MAPPER_RunInternal()",
+"Pause_Loop()",
+"WGET::Run()"
+]

src/gui/sdlmain.cpp

@@ -2915,6 +2915,15 @@ int main(int argc, char* argv[]) {
 	LOG_MSG("---");
 
 	/* Init SDL */
+#if SDL_VERSION_ATLEAST(2,0,0) && defined(EM_ASYNCIFY)
+	/* SDL calling emscripten_sleep() would be unnecessary, and would also
+	 * require many more functions to be processed via asyncify.
+	 * This was added in SDL 2.0.14, so it can cause compile errors with old
+	 * SDL. Compile errors are better than SDL calling emscripten_sleep()
+	 * and causing mysterious exceptions.
+	 */
+	SDL_SetHint(SDL_HINT_EMSCRIPTEN_ASYNCIFY, "0");
+#endif
 #if SDL_VERSION_ATLEAST(1, 2, 14)
 	/* Or debian/ubuntu with older libsdl version as they have done this themselves, but then differently.
 	 * with this variable they will work correctly. I've only tested the 1.2.14 behaviour against the windows version