Disable warnings as errors for STAGEautofeedback.

Compilation during STAGEautofeedback produces additional warnings
since inlining decisions with -fauto-profile are different from
other builds.

This patches disables warnings as errors for STAGEautofeedback.

Tested on x86_64-pc-linux-gnu.

ChangeLog:

	* Makefile.in: Disable warnings as errors for STAGEautofeedback