test failure when renames produce similar similarities
test illustrating tri-cyclic rename failure
Fix rename looped reference issues

This makes the diff rename tracking code more careful about the
order in which it processes renames and more thorough in updating
the mapping of correct renames when an earlier rename update
alters the index of a later matched pair.
Merge pull request #1659 from arrbee/rename-cycle-fixes

Diff rename detection cycle fixes
CMakeLists: fix zlib linker setup

b53671a (Search for zlib unconditional, 2012-12-18) changed things
around to always (even on windows, that's what the subject refers to)
call FIND_PACKAGE(ZLIB).

However, it did not correctly handle the case where ZLIB_LIBRARY is
cached, either by the user setting it manually or by an earlier
search.  In that case, the IF(ZLIB_FOUND) would not trigger (that
variable is not cached) and we'd instead use the built-in version.

000e689 (CMake: don't try to use bundled zlib when the system's path
is in the cache, 2013-05-12) tried to fix that, but it actually made
the problem worse: now with ZLIB_LIBRARY cached, _neither_ of the
blocks would execute, resulting in a linker error for me when trying
to build such a doubly-configured setup.

To fix the issue, we just trust CMake to do the right thing.  If
ZLIB_LIBRARY is set (either from user or cache) then the find_library
in FindZLIB.cmake will use that instead of searching again.  So we can
unconditionally (for real this time) call FIND_PACKAGE(ZLIB), and just
check its result.
Merge pull request #1660 from trast/tr/fix-zlib-configuration

CMakeLists: fix zlib linker setup