audiofile: regenerate configure to fix issues

Audiofile's shipped configure script is outdated so regenerate to fix
issues like:
http://autobuild.buildroot.net/results/659fd28b0a3fa15ecd1b32e8a08dd441465459c1/



Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>