Flat union branch names match the tag enum's member names. Omitted
branches default to "no members for this tag value".
Branch names starting with a digit get rejected like "'data' member
'0' has an invalid name". However, omitting the branch works.
This is because flat union tag values get checked twice: as enum
member name, and as union branch name. The former accepts leading
digits, the latter doesn't.
Branches whose names start with a digit therefore cannot have members.
Feels wrong. Get rid of the restriction by skipping the latter check.
This can expose c_name() to input it can't handle: a name starting
with a digit. Improve it to return a valid C identifier for any
input.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210323094025.3569441-9-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Commit message rewritten]
5fbc78dd36