[Rd] 87668 fails on Windows 10 with "pdflatex not found"

[Avraham Adler]

I see there have been a number of tweaks to the document build
recently (87650, 87654, 87658, 97660, 97661, etc.)

I tried building 87668 today on Windows 10 and received the error
below. Is this related?

Thank you,

Avi

building/updating vignettes for package 'grid' ...
processing 'displaylist.Rnw'
Error: compiling TeX file 'displaylist.tex' failed with message:
pdflatex is not available
Execution halted
building/updating vignettes for package 'parallel' ...
processing 'parallel.Rnw'
Error: compiling TeX file 'parallel.tex' failed with message:
pdflatex is not available
Execution halted
building/updating vignettes for package 'utils' ...
processing 'Sweave.Rnw'
Error: running Sweave on vignette
'C:/RDevel/avraham/R/trunk/src/library/utils/vignettes/Sweave.Rnw'
failed with message:
 chunk 2
Error in texi2dvi(file = file, pdf = TRUE, clean = clean, quiet = quiet,  :
  pdflatex is not available
Execution halted
make[2]: *** [Makefile.win:99: vignettes] Error 1
make[1]: *** [Makefile:345: vignettes] Error 2
make: *** [Makefile:395: distribution] Error 2