Merge branch 'jl/submodule-diff'

* jl/submodule-diff:
Performance optimization for detection of modified submodules
git status: Show uncommitted submodule changes too when enabled
Teach diff that modified submodule directory is dirty
Show submodules as modified when they contain a dirty work tree

diff --cc diff.c
Simple merge

diff --cc revision.c
Simple merge

diff --cc submodule.c
index 3007f7d5a6279c14a7c29efdc752dbbc41218c76,3f851deb6afad564a786912a7bb4f9069d697ec7..f657bee379a6bc0fc7d6bd263c32e1b7e3e61efc
--- 1/submodule.c
--- 2/submodule.c
+++ b/submodule.c
@@@ -4,8 -4,9 +4,9 @@@
  #include "diff.h"
  #include "commit.h"
  #include "revision.h"
+ #include "run-command.h"
  
 -int add_submodule_odb(const char *path)
 +static int add_submodule_odb(const char *path)
  {
        struct strbuf objects_directory = STRBUF_INIT;
        struct alternate_object_database *alt_odb;

diff --cc wt-status.c
Simple merge