rename configure.ac

Newer autotools are starting to complain with the old configure.in name.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
respect user CPPFLAGS/LDFLAGS

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
create dirs before installing into them

Doing `make install DESTDIR=$PWD/foo` fails because it doesn't create
the dirs it tries to install files into.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
ignore generated files

Signed-off-by: Mike Frysinger <vapier@gentoo.org>