readme: Add note about integer assertions

README.md

@@ -17,7 +17,9 @@ Lua headers and library.
 
 So far all tests have been run on recent versions of Arch Linux and FreeBSD, with following results.
 
- Compiler    | Lua 5.1  | Lua 5.2  | Lua 5.3
--------------|----------|----------|----------
- clang++ 3.6 | passes   | passes   | passes
- g++ 5.1     | passes   | passes   | passes
+ Compiler    | Lua 5.1 <sup>*</sup>  | Lua 5.2 <sup>*</sup> | Lua 5.3
+-------------|-----------------------|----------------------|----------
+ clang++ 3.6 | passes                | passes               | passes
+ g++ 5.1     | passes                | passes               | passes
+
+<sup>*</sup> Assertions relying on integers are ignored, due to integer quirks in Lua.