Cygwin: unlink: fix error checking order

Checking EPERM only makes sense if the file exists, so
let the EEXIST check change places with the EPERM check.

Add a debug statement to the EPERM condition.

Signed-off-by: Corinna Vinschen <[email protected]>
(cherry picked from commit b879cd1)

Author: github-cygwin

winsup/cygwin/syscalls.cc

@@ -1133,17 +1133,18 @@ unlink (const char *ourname)
       set_errno (EROFS);
       goto done;
     }
-  if (!win32_name.isondisk ())
-    {
-      set_errno (EPERM);
-      goto done;
-    }
   if (!win32_name.exists ())
     {
       debug_printf ("unlinking a nonexistent file");
       set_errno (ENOENT);
       goto done;
     }
+  if (!win32_name.isondisk ())
+    {
+      debug_printf ("unlinking a virtual file");
+      set_errno (EPERM);
+      goto done;
+    }
   else if (win32_name.isdir ())
     {
       debug_printf ("unlinking a directory");