[SV 64806] Fix MS-specific format specifier

* src/w32/w32os.c (osync_get_mutex): Fix format specifier.

src/w32/w32os.c

diff --git a/src/w32/w32os.c b/src/w32/w32os.c
index 7a0f99b..4c96b63 100644
--- a/src/w32/w32os.c
+++ b/src/w32/w32os.c
@@ -434,7 +434,7 @@
       /* Prepare the mutex handle string for our children.
          2 hex digits per byte + 2 characters for "0x" + null.  */
       mutex = xmalloc ((2 * sizeof (osync_handle)) + 2 + 1);
-      sprintf (mutex, "0x%Ix", (unsigned long long)(DWORD_PTR)osync_handle);
+      sprintf (mutex, "0x%I64x", (unsigned long long)(DWORD_PTR)osync_handle);
     }
 
   return mutex;