align with R-patched

git-svn-id: https://svn.r-project.org/R/trunk@66151 00db46b3-68df-0310-9c12-caf00c1e9a41
catch up with R-patched

git-svn-id: https://svn.r-project.org/R/trunk@66153 00db46b3-68df-0310-9c12-caf00c1e9a41
doc improvements

git-svn-id: https://svn.r-project.org/R/trunk@66154 00db46b3-68df-0310-9c12-caf00c1e9a41
Speed improvements in do_log and make log(...) work correctly.


git-svn-id: https://svn.r-project.org/R/trunk@66156 00db46b3-68df-0310-9c12-caf00c1e9a41