[cairo] pycairo autogen.sh test broken for automake-1.8 and later

[John Hunter]

Just wanted to let you know that the autogen.sh for pycairo in CVS is
broken for systems that have automake >1.7 (eg GNU automake 1.8.3)
because the 1.7 test is hardcoded in.  automake 1.8.3 works fine in
the build process, it's just the autogen.sh test that is broken.

Thanks!
JDH