Sync with 2.19.6

* maint-2.19:
  Git 2.19.6
  Git 2.18.5
  Git 2.17.6
  unpack_trees(): start with a fresh lstat cache
  run-command: invalidate lstat cache after a command finished
  checkout: fix bug that makes checkout follow symlinks in leading path

diff --cc cache.h
Simple merge

diff --cc compat/mingw.c
Simple merge

diff --cc git-compat-util.h
index d17360e89789403ece1d81278822e7469cd296a1,523676d6fd79dcf1aa2473419805894cfd043bd2..a6ad7459745ea36af27112e9633650dd0c8acd31
--- 1/git-compat-util.h
--- 2/git-compat-util.h
+++ b/git-compat-util.h
@@@ -345,14 -342,11 +345,19 @@@ typedef uintmax_t timestamp_t
  #define _PATH_DEFPATH "/usr/local/bin:/usr/bin:/bin"
  #endif
  
 +#ifndef platform_core_config
 +static inline int noop_core_config(const char *var, const char *value, void *cb)
 +{
 +      return 0;
 +}
 +#define platform_core_config noop_core_config
 +#endif
 +
+ int lstat_cache_aware_rmdir(const char *path);
+ #if !defined(__MINGW32__) && !defined(_MSC_VER)
+ #define rmdir lstat_cache_aware_rmdir
+ #endif
+ 
  #ifndef has_dos_drive_prefix
  static inline int git_has_dos_drive_prefix(const char *path)
  {

diff --cc run-command.c
Simple merge

diff --cc t/t0021-conversion.sh
Simple merge

diff --cc unpack-trees.c
index 545d5668fdf79015784cafcfbc24322b68e8927c,7e023daca3cf4c7d5683311502786a06e4d5e83a..dfea110b42ca04bc08bf68237360ad2c1de469c1
--- 1/unpack-trees.c
--- 2/unpack-trees.c
+++ b/unpack-trees.c
@@@ -391,11 -350,11 +391,14 @@@ static int check_updates(struct unpack_
        state.refresh_cache = 1;
        state.istate = index;
  
 +      if (o->clone)
 +              setup_collided_checkout_detection(&state, index);
 +
        progress = get_progress(o);
  
+       /* Start with clean cache to avoid using any possibly outdated info. */
+       invalidate_lstat_cache();
+ 
        if (o->update)
                git_attr_set_direction(GIT_ATTR_CHECKOUT);