cups: clean up autotools use

cups: clean up autotools use

Instead of hand-rolling a do_configure() simply use autotools and disable
autoheader (upstream uses a hand-generated config.h.in).

Also do_compile() doesn't need to pass SSLLIBS as configure uses pkgconfig to
find gnutls, LIBPNG and LIBJPEG are not used anywhere in the build system, and
LIBZ is detected correctly.

(From OE-Core rev: 9c25af5483280c5c753f981504eb373d6e58c7f3)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>