Fix definition of os.exit() in Lua 5.2+

Fixes #538

In Lua 5.2, os.exit() gained an additional boolean argument.

CHANGELOG.md

@@ -16,6 +16,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - `string.pack` and `string.unpack` now have proper function signatures in the Lua 5.3 standard library.
 - Moved `math.log` second argument addition from Lua 5.3 std lib to 5.2 std lib
 - `undefined_variable` now correctly errors when defining multiple methods in undefined tables
+- Corrected `os.exit` definition in Lua 5.2 standard library
 
 ## [0.25.0](https://github.com/Kampfkarren/selene/releases/tag/0.25.0) - 2023-03-12
 ### Added

selene-lib/default_std/lua52.yml

@@ -68,6 +68,12 @@ globals:
       - type: number
       - required: false
         type: number
+  os.exit:
+    args:
+      - required: false
+        type: number
+      - required: false
+        type: bool
   package.config:
     property: read-only
   rawlen: