[Bug c/105863] RFE: C23 #embed

["jsm28 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105863

--- Comment #9 from Joseph S. Myers <jsm28 at gcc dot gnu.org> ---
The most straightforward and most important case to optimize is the one where
the #embed expansion lies entirely inside a single character array initializer
(possibly with some integer constants before or after it in the initializer -
whether coming from the prefix and suffix parameters to #embed or otherwise) -
in which case the initializer can be converted internally to a STRING_CST.
Cases that aren't within a character array initializer like that are harder to
optimize (might require additional internal representation beyond the front
end), and probably also less important to optimize initially.