Fix: [Emscripten] compile with exceptions enabled, as our AIs depend on it

Also parts of the saveload code does, and some other places. This
does slow down builds, but for most computers this will not be
measurable. At least, the ones I had access to I could not find
a difference in FPS, mainly as that is heavily limited by the Hz
of the screens of the computer.

Either way, it is better to have a full functional game than a
fast one in my opinion

CMakeLists.txt

@@ -242,6 +242,8 @@ if(EMSCRIPTEN)
     # Allow heap-growth, and start with a bigger memory size.
     target_link_libraries(WASM::WASM INTERFACE "-s ALLOW_MEMORY_GROWTH=1")
     target_link_libraries(WASM::WASM INTERFACE "-s INITIAL_MEMORY=33554432")
+    target_link_libraries(WASM::WASM INTERFACE "-s DISABLE_EXCEPTION_CATCHING=0")
+    add_definitions(-s DISABLE_EXCEPTION_CATCHING=0)
 
     # Export functions to Javascript.
     target_link_libraries(WASM::WASM INTERFACE "-s EXPORTED_FUNCTIONS='[\"_main\", \"_em_openttd_add_server\"]' -s EXTRA_EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")