build: update autogen.sh to comply to gnome-rules

There are some subtle rules about NOCONFIGURE vars and sub-dir invocations
required by the gnome-build-chain. Fix these so we're more easy to use.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
build: add missing basic autoconf checks

Two missing basic checks that should be provided for better compatibility
and error checking.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: invert pro-controller y-axes

We drew them in the wrong direction (the kernel reported the wrong
values). Invert them so it's correct again.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>