[webkit-efl] HEADS-UP: Change to the default behavior of build-webkit and jhbuild

[Raphael Kubo da Costa]

Hi everyone,

Some of you may have noticed that after bug 93208 landed, the jhbuild
dependencies would always be updated regardless of any configuration
change, which was quite annoying.

Since r125862, we behave more similarly to the WebKitGTK+ port in two
ways: first, build-webkit will update the jhbuild modules *only* if
--update-efl is passed as an argument; secondly, jhbuild itself will
only be used if $WEBKITOUTPUTDIR/Dependencies exists.

Important corollaries:
 - If you check out a clean tree and run build-webkit, jhbuild will
 *not* be used by default and the system libraries will be used until
 build-webkit --update-efl is used and $WEBKITOUTPUTDIR/Dependencies
 starts existing.

 - Even if you have already bootstrapped jhbuild, you need to
   periodically (or always) pass --update-efl to build-webkit for it to
   check if any of its modules need to be updated. So if we bump some
   dependency version in, say, OptionsEfl.cmake, you may experience some
   CMake failure if you don't update your jhbuild modules.

The bots shouldn't experience any change, by the way, since --update-efl
is now run by default by them.