Enhancements:
-------------

* update default MACOSX_DEPLOYMENT_TARGET to 10.9  #2293
* modernize pin_depends so that it works with conda render  #2294
* environment variable pass-throughs now respect variant (env var highest priority; variant, finally default)  #2310

Bug fixes:
----------

* fix run_exports getting picked up transitively  #2298
* fix default compiler not having platform  #2300
* fix CONDA_PY formatting (should not have period).  PY_VER does have period.  #2304
* update index before testing a package, so that that package is conda-installable.  #2308
* update index after moving a package after test failure, so that the index is current.  #2308
* fix --output-folder not being respected by --output preview of output path  #2309