Merge branch 'maint-1.7.7' into maint

* maint-1.7.7:
  docs: describe behavior of relative submodule URLs
  Documentation: read-tree --prefix works with existing subtrees
  Add MYMETA.json to perl/.gitignore

Documentation/git-read-tree.txt

@@ -83,11 +83,10 @@ OPTIONS
 
 --prefix=<prefix>/::
 	Keep the current index contents, and read the contents
-	of the named tree-ish under the directory at `<prefix>`. The
+	of the named tree-ish under the directory at `<prefix>`.
-	original index file cannot have anything at the path
+	The command will refuse to overwrite entries that already
-	`<prefix>` itself, nor anything in the `<prefix>/`
+	existed in the original index file. Note that the `<prefix>/`
-	directory.  Note that the `<prefix>/` value must end
+	value must end with a slash.
-	with a slash.
 
 --exclude-per-directory=<gitignore>::
 	When running the command with `-u` and `-m` options, the

Documentation/git-submodule.txt

@@ -79,7 +79,12 @@ to exist in the superproject. If <path> is not given, the
 <repository> is the URL of the new submodule's origin repository.
 This may be either an absolute URL, or (if it begins with ./
 or ../), the location relative to the superproject's origin
-repository. If the superproject doesn't have an origin configured
+repository (Please note that to specify a repository 'foo.git'
+which is located right next to a superproject 'bar.git', you'll
+have to use '../foo.git' instead of './foo.git' - as one might expect
+when following the rules for relative URLs - because the evaluation
+of relative URLs in Git is identical to that of relative directories).
+If the superproject doesn't have an origin configured
 the superproject is its own authoritative upstream and the current
 working directory is used instead.
 +

perl/.gitignore

@@ -1,5 +1,6 @@
 perl.mak
 perl.mak.old
+MYMETA.json
 MYMETA.yml
 blib
 blibdirs