* [msbuild] Rename and unify to IsMacEnabled
We previously had an MtouchTargetsEnabled and a separate
IsMacTargetsEnabled for iOS and XM, when both actually
meant the same thing: is a Mac enabled for building this
project?
Note that instead of "targets", we make it more generic,
since the condition can be used in a task, a property
group or whatever really, not just to enable/disable
certain targets.
Also, we call it Enabled, rather than Connected or
Available, since it's more natural to think that all such
tasks/targets are enabled when you're building locally
on the Mac. Connected wouldn't have been appropriate, and
Available would be confusing.
For backwards compatibility I've kepd the old MtouchTargetsEnabled
pointing to IsMacEnabled. We'll change our Windows targets
accordingly to also unify this property and how/where it's
set.
* [msbuild] Use full condition comparison for robustness
This is the proper way to use a boolean in a condition, and
prevents errors whenever the property is an empty string or
anything other than a boolean value.
Daniel Cazzulino
Rolf Bjarne Kvinge