Global renaming lists

[therontarigo]

Managing a list of identifiers that will be globally renamed in all instances can solve these limitations:

• unclean macros (macros containing references to identifiers other than their own arguments) break
• macro names are not shortened
• user-defined type names are not shortened (# 290 "Minifying structs ...")

Global renaming will be subject to some restrictions:

• Any variable or function whose name is a globally renamed identifier must be excluded from inlining, reordering, and dead code removal.
• Global renaming short names may not be reused for normal scoped renaming.

Managing a list of struct member names and their renamings can solve #290 "...and their members". Consistent struct member renaming avoids the issue of needing to know an expression's type.

Please leave a message before implementing a significant change, so that we can agree on the solution.

The implementations for each of these mechanisms are similar. In each case: it falls somewhat short of optimal renaming analysis, but the implementation is far simpler than for a fully general solution. Is this reasonable?

Exposing --global-renaming-list option to the user may be usable for workarounds in some situations.