Merge branch 'bw/config-h'

Fix configuration codepath to pay proper attention to commondir
that is used in multi-worktree situation, and isolate config API
into its own header file.

* bw/config-h:
  config: don't implicitly use gitdir or commondir
  config: respect commondir
  setup: teach discover_git_directory to respect the commondir
  config: don't include config.h by default
  config: remove git_config_iter
  config: create config.h

Author: gitster

advice.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "config.h"
 
 int advice_push_update_rejected = 1;
 int advice_push_non_ff_current = 1;

alias.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "config.h"
 
 struct config_alias_data {
 	const char *alias;

apply.c

@@ -8,6 +8,7 @@
  */
 
 #include "cache.h"
+#include "config.h"
 #include "blob.h"
 #include "delta.h"
 #include "diff.h"

archive-tar.c

@@ -2,6 +2,7 @@
  * Copyright (c) 2005, 2006 Rene Scharfe
  */
 #include "cache.h"
+#include "config.h"
 #include "tar.h"
 #include "archive.h"
 #include "streaming.h"

archive-zip.c

@@ -2,6 +2,7 @@
  * Copyright (c) 2006 Rene Scharfe
  */
 #include "cache.h"
+#include "config.h"
 #include "archive.h"
 #include "streaming.h"
 #include "utf8.h"

archive.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "config.h"
 #include "refs.h"
 #include "commit.h"
 #include "tree-walk.h"

attr.c

@@ -9,6 +9,7 @@
 
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "config.h"
 #include "exec_cmd.h"
 #include "attr.h"
 #include "dir.h"

bisect.c

@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "config.h"
 #include "commit.h"
 #include "diff.h"
 #include "revision.h"

branch.c

@@ -1,5 +1,6 @@
 #include "git-compat-util.h"
 #include "cache.h"
+#include "config.h"
 #include "branch.h"
 #include "refs.h"
 #include "remote.h"

builtin/add.c

@@ -4,6 +4,7 @@
  * Copyright (C) 2006 Linus Torvalds
  */
 #include "cache.h"
+#include "config.h"
 #include "builtin.h"
 #include "lockfile.h"
 #include "dir.h"