Make atomics less bad;

- Remove horrible stdatomic.h/threads.h shim
  - Compiler engineers are better at writing atomic/thread stuff than I am
  - LÖVR requires C11 threads and atomics now
  - Add /experimental:c11atomics for MSVC support
    - Requires VS 17.5 preview 2 (ca. 2023)
- Use atomics properly everywhere
  - Any variables used as arguments to atomic_* functions must be atomic
    - Including refcounts
    - Compiler warns about this now, which is good
  - Generally, only use atomic functions when needed
    - Regular assignment/operators on atomic variables are already atomic
- Add thread safe module initialization helper in util, use it everywhere

Author: bjornbytes

CMakeLists.txt

@@ -299,7 +299,6 @@ target_include_directories(lovr PRIVATE
   ${LOVR_LUA_INCLUDE}
   ${PROJECT_SOURCE_DIR}/src
   ${PROJECT_SOURCE_DIR}/src/modules
-  ${PROJECT_SOURCE_DIR}/src/lib/std
   ${PROJECT_SOURCE_DIR}/etc
 )
 
@@ -653,7 +652,7 @@ endfunction()
 if(WIN32)
   target_sources(lovr PRIVATE src/core/os_win32.c etc/lovr.rc)
   if(MSVC)
-    set_target_properties(lovr PROPERTIES COMPILE_FLAGS /wd4244)
+    target_compile_options(lovr PRIVATE /wd4244 /experimental:c11atomics)
     # Excuse anonymous union for type punning
     set_source_files_properties(src/util.c src/modules/graphics/graphics.c PROPERTIES COMPILE_FLAGS /wd4116)
     # Excuse unsigned negation for flag-magic bit math
@@ -669,10 +668,6 @@ if(WIN32)
   target_compile_definitions(lovr PRIVATE _CRT_SECURE_NO_WARNINGS)
   target_compile_definitions(lovr PRIVATE _CRT_NONSTDC_NO_WARNINGS)
 
-  if(MSVC_VERSION VERSION_LESS 1900)
-    target_compile_definitions(lovr PRIVATE inline=__inline snprintf=_snprintf)
-  endif()
-
   function(move_dll)
     if(TARGET ${ARGV0})
       add_custom_command(TARGET move_files POST_BUILD

src/api/l_headset.c

@@ -1148,7 +1148,7 @@ int luaopen_lovr_headset(lua_State* L) {
   }
   lua_pop(L, 1);
 
-  luax_atexit(L, lovrHeadsetDestroy);
   luax_assert(L, lovrHeadsetInit(&config));
+  luax_atexit(L, lovrHeadsetDestroy);
   return 1;
 }

src/core/gpu_vk.c

@@ -260,7 +260,7 @@ static struct {
   gpu_allocator allocators[GPU_MEMORY_COUNT];
   uint8_t allocatorLookup[GPU_MEMORY_COUNT];
   gpu_memory memory[1024];
-  gpu_thread_state* threads;
+  _Atomic(gpu_thread_state*) threads;
   gpu_morgue morgue;
 } state;