This blog is updated daily.
A general description is here.
System functions ‘access’, ‘chdir’ and ‘getcwd’ are now essential to configure R. (In practice they have been required for some time.)
The ‘popen’ system call is now required to build R. This ensures the availability of ‘system(intern = TRUE)’, ‘pipe()’ connections and printing from ‘postscript()’.
‘source(chdir = TRUE)’ failed to reset the working directory if it could not be determined - that is now an error.
Added workaround for the font problem with ‘X11(type = "cairo")’ and similar on Mac OS X whereby italic and bold styles were interchanged. (PR13463 amongst many other reports.)