multimedia/libass: Update to 0.17.4
Remove leftover USES=autoreconf from when we were fetching from GitHub.
We've been using pre-rolled releases since 0ffcdbd9d5e5 (2020-26-09) and
we don't patch the autotools files.
Elevate CPE_VENDOR and USE_LDCONFIG to USES block (portclippy).
Sort OPTIONS_DEFINE/OPTIONS_DEFAULT (portclippy).
Align whitespace within blocks for readability.