Log Message:
Changes  1.7.11.2:
 * On Cygwin, the platform pread(2) is not thread safe, just like our
   own compat/ emulation, and cannot be used in the index-pack
   program.  Makefile variable NO_THREAD_SAFE_PREAD can be defined to
   avoid use of this function in a threaded program.
 * "git add" allows adding a regular file to the path where a
   submodule used to exist, but "git update-index" does not allow an
   equivalent operation to Porcelain writers.
 * "git archive" incorrectly computed the header checksum; the symptom
   was observed only when using pathnames with hi-bit set.
 * "git blame" did not try to make sure that the abbreviated commit
   object names in its output are unique.
 * Running "git bundle verify" on a bundle that records a complete
   history said "it requires these 0 commits".
 * "git clone --single-branch" to clone a single branch did not limit
   the cloning to the specified branch.
 * "git diff --no-index" did not correctly handle relative paths and
   did not correctly give exit codes when run under "--quiet" option.
 * "git diff --no-index" did not work with pagers correctly.
 * "git diff COPYING HEAD:COPYING" gave a nonsense error message that
   claimed that the treeish HEAD did not have COPYING in it.
 * When "git log" gets "--simplify-merges/by-decoration" \ 
together with
   "--first-parent", the combination of these options makes the
   simplification logic to use in-core commit objects that haven't
   been examined for relevance, either producing incorrect result or
   taking too long to produce any output.  Teach the simplification
   logic to ignore commits that the first-parent traversal logic
   ignored when both are in effect to work around the issue.
 * "git ls-files --exclude=t -i" did not consider anything under t/ as
   excluded, as it did not pay attention to exclusion of leading paths
   while walking the index.  Other two users of excluded() are also
   updated.
 * "git request-pull $url dev" when the tip of "dev" branch \ 
was tagged
   with "ext4-for-linus" used the contents from the tag in the output
   but still asked the "dev" branch to be pulled, not the tag.
Also contains minor typofixes and documentation updates.