Merge branch 'master' into jgrpp

# Conflicts:
#	.gitignore
#	CMakeLists.txt
#	src/3rdparty/optional/optional.hpp
#	src/group_cmd.cpp
#	src/industry_cmd.cpp
#	src/misc_gui.cpp
#	src/video/sdl2_v.cpp

src/openttd.cpp

@@ -87,6 +87,11 @@
 
 #include "safeguards.h"
 
+#ifdef __EMSCRIPTEN__
+#	include <emscripten.h>
+#	include <emscripten/html5.h>
+#endif
+
 void CallLandscapeTick();
 void IncreaseDate();
 void MusicLoop();
@@ -123,6 +128,15 @@ void CDECL usererror(const char *s, ...)
 	ShowOSErrorBox(buf, false);
 	if (VideoDriver::GetInstance() != nullptr) VideoDriver::GetInstance()->Stop();
 
+#ifdef __EMSCRIPTEN__
+	emscripten_exit_pointerlock();
+	/* In effect, the game ends here. As emscripten_set_main_loop() caused
+	 * the stack to be unwound, the code after MainLoop() in
+	 * openttd_main() is never executed. */
+	EM_ASM(if (window["openttd_syncfs"]) openttd_syncfs());
+	EM_ASM(if (window["openttd_abort"]) openttd_abort());
+#endif
+
 	exit(1);
 }