On WinXP, R CMD config needs sh (and breaks without it) (PR#11484)

Full_Name: Laurent Gautier
Version: R-2.7.0patched (r45712)
OS: WinXP
Submission from: (NULL) (90.15.141.247)



On a WinXP box (that does not has "sh" in the %Path%,
R CMD config appears to break:

C:\>R CMD config
'sh' is not recognized as an internal or external command,
operable program or batch file.