Add defines for byond-tracy support (#70931)

Adds `USE_BYOND_TRACY`, which automatically loads a given
prof.dll/libprof.so using https://github.com/mafemergency/byond-tracy/.

Not intended for use in production, and we do not ship a copy of
byond-tracy. It is extremely easy to compile yourself, but if you're
someone interesting enough to play around with this then let me know and
I can just give you a build.

I'm going to be using this for init profiling.

.gitignore

@@ -213,6 +213,10 @@ aux*.dll
 libaux*.so
 aux*.pdb
 
+# byond-tracy, we intentionally do not ship this and do not want to maintain it
+prof.dll
+libprof.so
+
 # JavaScript tools
 **/node_modules
 

code/_compile_options.dm

@@ -54,9 +54,15 @@
 #define GC_FAILURE_HARD_LOOKUP
 #endif // REFERENCE_DOING_IT_LIVE
 
+// If this is uncommented, we do a single run though of the game setup and tear down process with unit tests in between
+// #define UNIT_TESTS
+
+// If this is uncommented, will attempt to load and initialize prof.dll/libprof.so.
+// We do not ship byond-tracy. Build it yourself here: https://github.com/mafemergency/byond-tracy/
+// #define USE_BYOND_TRACY
+
 // If defined, we will NOT defer asset generation till later in the game, and will instead do it all at once, during initiialize
 //#define DO_NOT_DEFER_ASSETS
-//#define UNIT_TESTS //If this is uncommented, we do a single run though of the game setup and tear down process with unit tests in between
 
 /// If this is uncommented, Autowiki will generate edits and shut down the server.
 /// Prefer the autowiki build target instead.

code/game/world.dm

@@ -34,6 +34,10 @@ GLOBAL_VAR(restart_counter)
  * All atoms in both compiled and uncompiled maps are initialized()
  */
 /world/New()
+#ifdef USE_BYOND_TRACY
+	#warn USE_BYOND_TRACY is enabled
+	init_byond_tracy()
+#endif
 
 	log_world("World loaded at [time_stamp()]!")
 
@@ -385,6 +389,22 @@ GLOBAL_VAR(restart_counter)
 /world/proc/on_tickrate_change()
 	SStimer?.reset_buckets()
 
+/world/proc/init_byond_tracy()
+	var/library
+
+	switch (system_type)
+		if (MS_WINDOWS)
+			library = "prof.dll"
+		if (UNIX)
+			library = "libprof.so"
+		else
+			CRASH("Unsupported platform: [system_type]")
+
+	var/init_result = call(library, "init")()
+	if (init_result != "0")
+		CRASH("Error initializing byond-tracy: [init_result]")
+
+
 /world/Profile(command, type, format)
 	if((command & PROFILE_STOP) || !global.config?.loaded || !CONFIG_GET(flag/forbid_all_profiling))
 		. = ..()