Enable ashpd on FreeBSD
Upstreaming as FreeBSD has xdg-desktop-portal package.
I don't understand why platform gatekeeping is necessary given ashpd
builds fine without xdg-desktop-portal
while Amberol runs fine if built with ashpd
but xdg-desktop-portal
hasn't been installed yet. For example, neither video-trimmer nor Authenticator limit ashpd
to linux
.