Configure: Use AC_TRY_RUN() to check that --enable-gcc-hardening works
Split off [comment:3:ticket:27460 #27460 (moved) Comment 3]:
maybe in 0.3.5 we should change the implementation of gcc-hardening so that it does an AC_TRY_RUN() to see whether it can use these compiler flags safely. That could be another ticket, though.
When we merge to 0.3.5, we should also revert #27460 (moved).