Target specific architectures for OS X and iOS.

This variable is used to initialize the OSX_ARCHITECTURES property on each target as it is creaed. See that target property for additional information.

The value of this variable should be set prior to the first project() or enable_language() command invocation because it may influence configuration of the toolchain and flags. It is intended to be set locally by the user creating a build tree.

This variable is ignored on platforms other than OS X.