Merge branch 'hv/submodule-config'

The gitmodules API accessed from the C code learned to cache stuff
lazily.

* hv/submodule-config:
  submodule: allow erroneous values for the fetchRecurseSubmodules option
  submodule: use new config API for worktree configurations
  submodule: extract functions for config set and lookup
  submodule: implement a config API for lookup of .gitmodules values

diff --cc .gitignore
Simple merge

diff --cc Makefile
index 34101e2,5d9a63f..e326fa0
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -784,9 -785,9 +785,10 @@@ LIB_OBJS += strbuf.
  LIB_OBJS += streaming.o
  LIB_OBJS += string-list.o
  LIB_OBJS += submodule.o
+ LIB_OBJS += submodule-config.o
  LIB_OBJS += symlinks.o
  LIB_OBJS += tag.o
 +LIB_OBJS += tempfile.o
  LIB_OBJS += trace.o
  LIB_OBJS += trailer.o
  LIB_OBJS += transport.o

diff --cc builtin/checkout.c
index 52d59eb,f1f168d..bc703c0
--- 1/builtin/checkout.c
--- 2/builtin/checkout.c
+++ b/builtin/checkout.c
@@@ -18,7 -18,10 +18,8 @@@
  #include "xdiff-interface.h"
  #include "ll-merge.h"
  #include "resolve-undo.h"
+ #include "submodule-config.h"
  #include "submodule.h"
 -#include "argv-array.h"
 -#include "sigchain.h"
  
  static const char * const checkout_usage[] = {
        N_("git checkout [<options>] <branch>"),

diff --cc builtin/fetch.c
Simple merge

diff --cc diff.c
Simple merge

diff --cc submodule.c
Simple merge