util/osdep: Improve error report by calling error_setg_win32()

Use error_setg_win32() which adds a hint similar to strerror(errno)).

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200228100726.8414-3-philmd@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

util/osdep.c

@@ -82,8 +82,8 @@ static int qemu_mprotect__osdep(void *addr, size_t size, int prot)
     DWORD old_protect;
 
     if (!VirtualProtect(addr, size, prot, &old_protect)) {
-        error_report("%s: VirtualProtect failed with error code %ld",
-                     __func__, GetLastError());
+        g_autofree gchar *emsg = g_win32_error_message(GetLastError());
+        error_report("%s: VirtualProtect failed: %s", __func__, emsg);
         return -1;
     }
     return 0;