bash: fix configuration

Patch bash32-011 modifies the configure.in script. Therefor we need to
run autoconf before launching the configure script. Otherwise, once
the configure script called, the makefile's dependencies over
configure.in will relaunch autoconf without options/environnement
variables we usually set when calling configure.

[Peter: use our own host-autoconf instead of what's on the host]
Signed-off-by: Lionel Landwerlin <llandwerlin@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>