Problem in method's Makefile?

Hi there ...

Not too long after the switch to using Subversion I tried to checkout &
build R but encountered an error - and being short on time at that point
put it off to look at later.  So today I sat down again and was
encountering this error every time I would attempt to build:

 dumping R code in package 'methods'
 Saving namespace image ...
 initializing class and method definitions now ...done
 <environment: namespace:methods>
 usage: touch [-acfm] [-r file] [-t [[CC]YY]MMDDhhmm[.SS]] file ...
 *** Error code 1

I traced this down to the Makefile in methods:
$(top_builddir)/library/$(pkg)/R/$(pkg).rdb: $(top_builddir)/library/$(pkg)/R/all.rda
        @echo "tools:::makeLazyLoading(\"$(pkg)\")" | \
          R_DEFAULT_PACKAGES=NULL LC_COLLATE=C $(R_EXE) --slave >
/dev/null
        @cat /dev/null > $(top_builddir)/library/$(pkg)/R/all.rda
        @touch $^


I'm not sure what it is about that touch call, but commenting it out
causes things to build normally.  When I try to echo '$^', it appears to
be an empty string.

This is all on a FreeBSD machine - I'm assuming it is somehow OS specific
as this would have come up a bunch of times if it wasn't.