- And map xbuild properties to msbuild ones for fallback paths
`XBUILD_FRAMEWORK_FOLDERS_PATH -> TargetFrameworkFallbackSearchPaths`
`MSBuildExtensionsPath -> MSBuildExtensionsPathFallbackPathsOverride`
Note:
Earlier with xbuild, the order of lookup for (example)
`MSBuildExtensionsPath` was:
1. The value of $(MSBuildExtensionsPath), which we were setting to
the in-tree path
2. /Library/Frameworks/Mono.framework/External/xbuild on osx
3. $prefix/lib/mono/xbuild (default location)
And with the above changes, it will be:
1. The value of $(MSBuildExtensionsPath), which we are no longer
setting, so the default path : $prefix/lib/mono/xbuild
2. The in-tree path, via $(MSBuildExtensionsPathFallbackPathsOverride)
3. /Library/Frameworks/Mono.framework/External/xbuild on osx
Since, XI/XM targets are used via fallback path
`/Library/Frameworks/Mono.framework/External/xbuild`, the default
location doesn't matter. And the order of the remaining two remains the
same.
The same thing applies to the target frameworks also.
* [builds] Don't install symlinks to iOS/Classic assemblies in the iOS/Unified profile.
* [fsharp] Don't install symlinks to iOS/Classic assemblies in the iOS/Unified profile.
The symlinks won't quite work once we remove the iOS/Classic assemblies.