Version 2.4.1 is available upstream. Please consider updating! It seems that version 2.4.1 is available upstream, while the latest version in the Gentoo tree is 2.4.0. You think this warning is false? Read more about it here.
xa is a high-speed, two-pass portable cross-assembler. It
understands mnemonics and generates code for NMOS 6502s (such as
6502A, 6504, 6507, 6510, 7501, 8500, 8501, 8502 ...), CMOS 6502s
(65C02 and Rockwell R65C02) and the 65816.