cmd: MOVEing a file to itself is a no-op

[Frédéric Delanoy]

For directory files, this still gives errors (as windows does)
---
 programs/cmd/builtins.c                  |    7 +++++++
 programs/cmd/tests/test_builtins.cmd.exp |    4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/programs/cmd/builtins.c b/programs/cmd/builtins.c
index 79e1ced..eaad4e2 100644
--- a/programs/cmd/builtins.c
+++ b/programs/cmd/builtins.c
@@ -1590,6 +1590,13 @@ void WCMD_move (void)
   if (hff == INVALID_HANDLE_VALUE)
     return;
 
+  /* Moving a file to itself is a no-op */
+  if (!strcmpW(input, output)) {
+    DWORD attribs = GetFileAttributesW(input);
+    if (attribs != INVALID_FILE_ATTRIBUTES && !(attribs & FILE_ATTRIBUTE_DIRECTORY))
+      return;
+  }
+
   do {
     WCHAR  dest[MAX_PATH];
     WCHAR  src[MAX_PATH];
diff --git a/programs/cmd/tests/test_builtins.cmd.exp b/programs/cmd/tests/test_builtins.cmd.exp
index 20e5d12..d61b75b 100644
--- a/programs/cmd/tests/test_builtins.cmd.exp
+++ b/programs/cmd/tests/test_builtins.cmd.exp
@@ -616,8 +616,8 @@ file move succeeded
 @todo_wine at bar@or_broken at baz
 read-only files are moveable
 file moved in subdirectory
- at todo_wine@moving a file to itself is a no-op at or_broken@moving a file to itself should be a no-op!
- at todo_wine@ErrorLevel: 0 at or_broken@ErrorLevel: 1
+moving a file to itself is a no-op at or_broken@moving a file to itself should be a no-op!
+ErrorLevel: 0 at or_broken@ErrorLevel: 1
 ... directory move ...
 simple directory move succeeded
 moving a directory to itself gives error; errlevel 1
-- 
1.7.7