In all practical situations, the resolver visibility is static.
Requested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: so (emaste)
Differential revision: https://reviews.freebsd.org/D20281
In particular, use ifuncs for __getcontextx_size(), also calculate the
size of the extended save area in resolver. Same for __fillcontextx2().
Sponsored by: The FreeBSD Foundation
MFC after: 1 week