Current in-portage version is 1.2, but latest version released is 3.0 Renaming the ebuild and the patches makes it compile, but it tries to overwrite the file /usr/games/bin/advmenu in case it is installed, so maybe removing it somehow from compilation/install is enough
Thank you for your report.
[master 5484ca5ad38c] games-emulation/advancemame: Version bump 2 files changed, 92 insertions(+) create mode 100644 games-emulation/advancemame/advancemame-3.7.ebuild