assign printf format attribute to log_callback

Let the compiler detect and flag improper log messages at compile time.

BUG=chromium-os:34226
TEST=libevdev and cmt build clean

Change-Id: Ic339374361ab8bac7badc272e5dd33f9c8904ba6
Reviewed-on: https://gerrit.chromium.org/gerrit/32546
Reviewed-by: Andrew de los Reyes <adlr@chromium.org>
Commit-Ready: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>
1 file changed
tree: 324c6f31d41cd255eb2a94ef9b038a9a7359c598
  1. include/
  2. src/
  3. common.mk
  4. Makefile