Merged requested to merge kelnos/xfce4-dev-tools:new-feature-and-binary-macros into master
I've found that I keep copy-pasting these snippets over and over, so I think they might be useful as macros. I am very much in need of
XDT_CHECK_OPTIONAL_FEATURE, but if y'all don't think
XDT_CHECK_PKG_BINARY is worth it, I can drop that commit.