add luajit to meson includes

HeliumAnt · HeliumAnt · commit c2b4233f9d97 · 2024-02-17T21:18:06.000+01:00
this really doesn't feel like the right solution btw
diff --git a/external/meson.build b/external/meson.build
@@ -1,3 +1,4 @@
 subdir('include')
 subdir('lib')
 subdir('sources')
+external_inc_dirs += include_directories('sources/LuaJIT-2.1/src')
