Merge branch 'rs/strbuf-getcwd'

Reduce the use of fixed sized buffer passed to getcwd() calls
by introducing xgetcwd() helper.

* rs/strbuf-getcwd:
  use strbuf_add_absolute_path() to add absolute paths
  abspath: convert absolute_path() to strbuf
  use xgetcwd() to set $GIT_DIR
  use xgetcwd() to get the current directory or die
  wrapper: add xgetcwd()
  abspath: convert real_path_internal() to strbuf
  abspath: use strbuf_getcwd() to remember original working directory
  setup: convert setup_git_directory_gently_1 et al. to strbuf
  unix-sockets: use strbuf_getcwd()
  strbuf: add strbuf_getcwd()

Documentation/technical/api-strbuf.txt

@@ -307,6 +307,16 @@ same behaviour as well.
 	use it unless you need the correct position in the file
 	descriptor.
 
+`strbuf_getcwd`::
+
+	Set the buffer to the path of the current working directory.
+
+`strbuf_add_absolute_path`
+
+	Add a path to a buffer, converting a relative path to an
+	absolute one in the process.  Symbolic links are not
+	resolved.
+
 `stripspace`::
 
 	Strip whitespace from a buffer. The second parameter controls if