[R] Error in untar2(tarfile, files, list, exdir) : unsupported entry type ‘x’

[Christopher Bare]

For posterity, this thread was continued on the R-SIG-Mac mailing list
under the same subject. Prof. Brian Ripley was kind enough to point
out an easy work around:

R CMD INSTALL now uses the internal untar() in package utils:
this ensures that all platforms can install bzip2- and
xz-compressed tarballs. In case this causes problems (as it
has on some Windows file systems when run from Cygwin tools)
it can be overridden by the environment variable
R_INSTALL_TAR: setting this to a modern external tar program
will speed up unpacking of large (tens of Mb or more) tarballs.

I suspect that the origin of the non-standard tar block types was that
user accounts and groups on my Mac are managed by Active Directory.
The same commands work on another Snow Leopard Mac with locally
managed accounts.

-chris