RelNotes/1.7.7.1: setgid bit patch is about fixing "git init" via Makefile setting

The change was actually about "git init -s" which sets the setgid bit on
SysV-style systems to allow shared access to a repository, and can provoke
errors on BSD-style systems, depending on how permissive the filesystem in
use wants to be.

More to the point, the patch was just taking a fix that arrived for
FreeBSD in v1.5.5 days and making it also apply to machines using an
(obscure) GNU userland/FreeBSD kernel mixture.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: jrn

Documentation/RelNotes/1.7.7.1.txt

@@ -5,8 +5,9 @@ Fixes since v1.7.7
 ------------------
 
  * On some BSD systems, adding +s bit on directories is detrimental
-   (it is not necessary on BSD to begin with). The installation
-   procedure has been updated to take this into account.
+   (it is not necessary on BSD to begin with). "git init --shared"
+   has been updated to take this into account without extra makefile
+   settings on platforms the Makefile knows about.
 
  * After incorrectly written third-party tools store a tag object in
    HEAD, git diagnosed it as a repository corruption and refused to