x86_64 is used as a baseline: the "x86_64" entry, whatever status it has,
is transformed into "all", and then the other entries in ARCHITECTURES
either dropped or rearranged appropriately.
* Enable 2nd arch and drop documentation when building for them.
* Add devel:lib{x11,xcb,xau} to REQUIRES_devel.
* Add $secondaryArchSuffix to cmd:libtoolize in BUILD_PREREQUIRES.
* HOMEPAGE: http://xorg.freedesktop.org/ moved to https://www.x.org/.
* ARCHITECTURES: Mark as tested on x86 and x86_64.