qapi: Store pragma state in QAPISourceInfo, not global state

The frontend can't be run more than once due to its global state.
A future commit will want to do that.

Recent commit "qapi: Move context-sensitive checking to the proper
place" got rid of many global variables already, but pragma state is
still stored in global variables (that's why a pragma directive's
scope is the complete schema).

Move the pragma state to QAPISourceInfo.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20191018074345.24034-3-armbru@redhat.com>
1 file changed