Backport of anyNA for R versions < 3.2.0.
backports: Reimplementations of Functions Introduced Since R-3.0.0
Backport of capture.output for R < 3.3.0
Backport of dQuote and sQuote for R < 3.6.0
Backports of wrappers around 'file.info' for R < 3.2.0
Import backported functions into your package
Backport of warningCondition and errorCondition for R < 3.6.0