deprecate CC < 4.0 licences

git-svn-id: https://svn.r-project.org/R/trunk@66252 00db46b3-68df-0310-9c12-caf00c1e9a41
clarification

git-svn-id: https://svn.r-project.org/R/trunk@66254 00db46b3-68df-0310-9c12-caf00c1e9a41
update to match R-patched

git-svn-id: https://svn.r-project.org/R/trunk@66256 00db46b3-68df-0310-9c12-caf00c1e9a41
Update information on Unix-like binaries.

git-svn-id: https://svn.r-project.org/R/trunk@66258 00db46b3-68df-0310-9c12-caf00c1e9a41
Have .encode_numeric_version() pad to common length with trailing zeros.
Add [<-.numeric_version().

git-svn-id: https://svn.r-project.org/R/trunk@66259 00db46b3-68df-0310-9c12-caf00c1e9a41
Typo.

git-svn-id: https://svn.r-project.org/R/trunk@66260 00db46b3-68df-0310-9c12-caf00c1e9a41