This is needed later in the program when doing unveil on the path of
"/tmp/session/%sid/portal/clipboard", because %sid is translated to the
root session ID which therefore relies on access to the /proc/all node.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
A SPICE agent communicates with the host OS to provide nifty features
like clipboard sharing :^)
This patch implements only plain-text clipboard sharing.
See: github.com/freedesktop/spice-protocol/blob/master/spice/vd_agent.h
