Undocument search features that no longer exist

Due to the fragility of the code, this functionality was removed in
recent refactorings of the tap code.

It is possible to restore these features, but it needs to be done in
a cleaner, more maintainable way.

Closes #29585.
gnutls 3.2.14
gnutls: update 3.2.14 bottle.
Share code for sanitizing ENV between both build environments
compcert: allow arch flags

Fixes #29569.
menhir 20140422
compcert 2.3pl2
required c++11 version of boost
Merge branch 'master' into cpp-netlib