[Rd] Building package with R 2.6.0 on Windows/Cygwin gives error with tar

[Kevin Wright]

My setup:
Windows XP, R-2.6.0, Cygwin (not the Rtools version)

When I tried to build a package, I was given this message:
tar: c\:/X/Rpkgs/Drydown_1.41.tar: Cannot open: Input/Output error

Even manually typing the following caused the same error:
tar chf 'c:/X/Rpkgs/Drydown_1.41.tar' Drydown

I looked at the 2.5.1 and 2.6.0 build scripts.  After restoring this
section to the 2.6.0 build script:
  ## workaround for paths in Cygwin tar
  $filepath =~ s+^([A-Za-z]):+/cygdrive/\1+;
  }
then $filepath evaluates to
  /cygdrive/c/X/Rpkgs/Drydown_1.41.tar
and I was able to build packages again.

(Posted in case someone else has the same problem and/or finds this useful.)

Kevin Wright