anchor.diff:  REM - BEGIN CONFIGURATION VARIABLES -
   REM ---------------------------------
   
  -SET "CRAN=http://cran.r-project.org"
  -SET "RTOOLS_VERSION=33"
  -SET "ROOT_DIR=C:\R-src"
  -SET "R_HOME=C:\R-src\trunk"
  -SET "RTOOLS_BIN_DIR=C:\Rtools\bin"
  -SET "TMPDIR=C:\tmp"
  +IF NOT DEFINED WGET (
  +	SET "WGET=wget"
  +)
  +
  +IF NOT DEFINED SVN (
  +	SET "SVN=svn"
  +)
  +
  +IF NOT DEFINED ROOT_DIR (
  +	SET "ROOT_DIR=C:\R-src"
  +)
  +
  +if NOT DEFINED RTOOLS_DIR (
  +	SET "RTOOLS_DIR=C:\Rtools"
  +)
  +
  +IF NOT DEFINED RTOOLS_BIN_DIR (
  +	SET "RTOOLS_BIN_DIR=C:\Rtools\bin"
  +)
  +
  +IF NOT DEFINED TMPDIR (
  +	SET "TMPDIR=C:\tmp"
  +)
   
   REM -------------------------------
   REM - END CONFIGURATION VARIABLES -
   REM -------------------------------
  +
  +SET "CRAN=http://cran.r-project.org"
  +SET "RTOOLS_VERSION=33"
  +
  +REM Ensure that some essential tools are on the PATH.
  +WHERE /Q %WGET% || (
  +	ECHO 'wget' not found on PATH; exiting
  +	exit /b
  +)
  +
  +where /Q %SVN% || (
  +	ECHO 'svn' not found on PATH; exiting
  +	exit /b
  +)
  +
   
   REM Set the current directory.
   if not exist "%ROOT_DIR%" (
  
positive.code: REM URI to RTools.exe
  SET "RTOOLS_URL=%CRAN%/bin/windows/Rtools/Rtools%RTOOLS_VERSION%.exe"
  
  REM Download Rtools.
  wget -c %RTOOLS_URL%
  
  REM Install Rtools.
  SET "RTOOLS_INSTALLER=.\Rtools%RTOOLS_VERSION%.exe"
  "%RTOOLS_INSTALLER%" /VERYSILENT
  
  REM Download the R sources. Get the latest R-devel sources using SVN.
  REM
  
negative.code: REM Be sure to place the installed binary directory on your PATH.
  svn checkout https://svn.r-project.org/R/trunk/
  cd trunk
  
  REM Copy in the 'extras' for a 64bit build. This includes tcltk
  REM plus some other libraries. Note that the R64 directory should
  