Building on Mac OS X 10.7

[Tor Lillqvist]

> * --with-macosx-version-min-required=10.6 (instead of 10.7) is needed at
> least for the moz and python modules.

If I recall correctly, using --with-macosx-version-min-required=10.7
even in a build with no mozilla on python will break in vcl thanks to
it using deprecated API (deprecated already in the 10.4 SDK...), which
has been finally removed completely from the 10.7 SDK.

--tml