win32: prevent stat(2) from updating access times

The WIN32 implementation of stat(2) reads the contents of some files
to see if they're executable.  This may update the file access time.
Avoid this by a special call to SetFileTime() after opening the file.

For details see:

   https://devblogs.microsoft.com/oldnewthing/20111010-00/?p=9433
   https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-setfiletime

File access times aren't updated by default in recent versions of
Windows.  This commit is only necessary if updating of file access
times is explicitly enabled:

   fsutil behavior set DisableLastAccess 0

1 files changed, 19 insertions, 4 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index 606a48319..8216f2e53 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -432,7 +432,10 @@ mode_t mingw_umask(mode_t new_mode)
  */
 static int has_exec_format(const char *name)
 {
-        int n, sig;
+        HANDLE fh;
+        int fd = -1;
+        ssize_t n;
+        int sig;
         unsigned int offset;
         unsigned char buf[1024];
 
@@ -440,8 +443,20 @@ static int has_exec_format(const char *name)
         if (is_suffixed_with_case(name, ".dll"))
                 return 0;
 
-        n = open_read_close(name, buf, sizeof(buf));
-        if (n < 4)      /* at least '#!/x' and not error */
+        /* Open file and try to avoid updating access time */
+        fh = CreateFileA(name, GENERIC_ALL, 0, NULL, OPEN_EXISTING, 0, NULL);
+        if (fh != INVALID_HANDLE_VALUE) {
+                FILETIME last_access = { 0xffffffff, 0xffffffff };
+
+                SetFileTime(fh, NULL, &last_access, NULL);
+                fd = _open_osfhandle((intptr_t)fh, O_RDONLY);
+        }
+
+        if (fd < 0)
+                return 0;
+
+        n = read_close(fd, buf, sizeof(buf));
+        if (n < 4) /* Need at least a few bytes and no error */
                 return 0;
 
         /* shell script */
@@ -453,7 +468,7 @@ static int has_exec_format(const char *name)
          * Poke about in file to see if it's a PE binary.  I've just copied
          * the magic from the file command.
          */
-        if (buf[0] == 'M' && buf[1] == 'Z') {
+        if (buf[0] == 'M' && buf[1] == 'Z' && n > 0x3f) {
                 offset = (buf[0x19] << 8) + buf[0x18];
                 if (offset > 0x3f) {
                         offset = (buf[0x3f] << 24) + (buf[0x3e] << 16) +