New backported LuaJIT v3 syntax breaks debugger line info

[vaisest]

This is probably similar to #354.

LuaJIT is adding new syntax in its v3 version: LuaJIT/LuaJIT#1092

The document is not fully relevant yet, but parts of the v3 syntax were backported to v2.1: LuaJIT/LuaJIT#1476

These features seem to break the debugger, and due to Mike being Mike, the new syntax was not a new release version. This means that the syntax will probably start appearing in new projects quite quickly.

Here's a list of the currently backported extensions:

Backported extensions:

• Bit Operators: unary ~, binary & | ~ << >> ~>>
• Customary Operators ! && || !=
• Ternary ?: conditional operator
• Safe Navigation Operator ?.
• nil-Coalescing Operator ??
• Compound Assignment Operators += -= *= …
• continue Statement
• const Declaration
• Short Function Expression
• Underscores in Number Literals