Fix the value of default-directory upon startup on MS-Windows

* src/w32.c (w32_get_current_directory): New function.
(GetCachedVolumeInformation, init_environment): Use it.
(w32_init_current_directory): New function.
* src/w32.h (w32_init_current_directory): Add prototype.
* src/emacs.c (main) [WINDOWSNT]: Use w32_init_current_directory
to get the accurate value of cwd.  This is needed to record
the correct directory in emacs_wd, which is now initialized
way earlier in the startup process, when init_environment was
not yet called.  For details, see the problems reported in
http://lists.gnu.org/archive/html/emacs-devel/2018-12/msg00068.html.
Reported by Angelo Graziosi <angelo.g0@libero.it>.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/w32.h b/src/w32.h
index 42b3d98245f..5054b400c5b 100644
--- a/src/w32.h
+++ b/src/w32.h
@@ -201,6 +201,7 @@ extern int  codepage_for_filenames (CPINFO *);
 extern Lisp_Object ansi_encode_filename (Lisp_Object);
 extern int  w32_copy_file (const char *, const char *, int, int, int);
 extern int  w32_accessible_directory_p (const char *, ptrdiff_t);
+extern void w32_init_current_directory (void);
 
 extern BOOL init_winsock (int load_now);
 extern void srandom (int);