The time zone format optimization discussed in #6878 won't be done in ICU4C 4.2. This ticket is used for porting the ICU4J implementation to ICU4C.
This work is done in ICU4C in our sources. Will have reviewed on open source branch soon.
Changes commited to branch, ready for review.
Committed to trunk (where they were supposed to be) instead of branch.
-r28687