c: Support volatile keyword
c: Support __attribute__((deprecated("message")))
c: Improve cast/parentheses expression disambiguation
c: Support __attribute__((alloc_size))
c: Support pure/const/format attributes
error reports: Don't show the extra context lines

It's too much clutter in the "TODO: unknown construct" notes...
c: Support may_alias/sentinel/format_arg/unused attributes
fbfrog.bi: Remove ASTNODE forward declaration (no longer needed)
util: Use ulong instead of uinteger for hashHash()
ast: Add ASTATTRIB_DUMMYID and replace strStartsWith(DUMMYID) checks
merging: Add hashing to avoid excessive astIsEqual() calls during LCS