Runtime should use LINK_LIBRARIES to link to ICU, since it is a static
archive, and we need this link dependency to be propagated to the
libswiftSwiftCore library. I have no idea why it linked correctly
worked before.
Swift SVN r25881
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
