[R] Daylight Savings Time unknown in R-2.2.1

[Brahm, David]

Under R-2.2.1, a POSIXlt date created with "strptime" has an unknown
Daylight Savings Time flag:

> strptime(20051208, "%Y%m%d")$isdst
[1] -1

This is true on both Linux (details below) and Windows.  It did not
occur under R-2.1.0.  Any ideas?  TIA!


> Sys.getenv("TZ")
TZ 
"" 

Version:
 platform = i686-pc-linux-gnu
 arch = i686
 os = linux-gnu
 system = i686, linux-gnu
 status = 
 major = 2
 minor = 2.1
 year = 2005
 month = 12
 day = 20
 svn rev = 36812
 language = R

Locale:
C

Search Path:
 .GlobalEnv, package:methods, package:stats, package:graphics,
package:grDevices, package:utils, package:datasets, Autoloads,
package:base

-- David Brahm (brahm at alum.mit.edu)