[tex-live] possible bug/regression in TL2016

[Jim Diamond]

Hi,

In TL2015, using (plain) pdftex, I can start with

\input ifpdf.sty
\input miniltx
\makeatletter
\def\Gin at driver{pdftex.def}
\input color.sty

and I get
This is pdfTeX, Version 3.14159265-2.6-1.40.16 (TeX Live 2015) (preloaded format=pdftex)
 restricted \write18 enabled.
**
entering extended mode
(/usr/local/texlive/2015/texmf-dist/tex/generic/oberdiek/ifpdf.sty)
*(/usr/local/texlive/2015/texmf-dist/tex/plain/graphics-pln/miniltx.tex)
*
*
*(/usr/local/texlive/2015/texmf-dist/tex/latex/graphics/color.sty
(/usr/local/texlive/2015/texmf-dist/tex/latex/latexconfig/color.cfg)
(/usr/local/texlive/2015/texmf-dist/tex/latex/pdftex-def/pdftex.def
(/usr/local/texlive/2015/texmf-dist/tex/generic/oberdiek/infwarerr.sty)
(/usr/local/texlive/2015/texmf-dist/tex/generic/oberdiek/ltxcmds.sty)
(/usr/local/texlive/2015/texmf-dist/tex/context/base/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
)))
*

That is, all is good.

But with TL2016 (both before and after recent updates), I get

This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=pdftex)
 restricted \write18 enabled.
**
entering extended mode
(/usr/local/texlive/2016/texmf-dist/tex/generic/oberdiek/ifpdf.sty)
*(/usr/local/texlive/2016/texmf-dist/tex/plain/graphics-pln/miniltx.tex)
*
*
*(/usr/local/texlive/2016/texmf-dist/tex/latex/graphics/color.sty
(/usr/local/texlive/2016/texmf-dist/tex/latex/graphics-cfg/color.cfg)
(/usr/local/texlive/2016/texmf-dist/tex/latex/graphics-def/pdftex.def
(/usr/local/texlive/2016/texmf-dist/tex/generic/oberdiek/infwarerr.sty)
(/usr/local/texlive/2016/texmf-dist/tex/generic/oberdiek/ltxcmds.sty)
! Undefined control sequence.
l.1569      \@ifpackageloaded
                             {pst-pdf}%          hv 20160630
? 


Have I been doing The Wrong Thing all along, and has TL2016 come to
smite me?  Or should I be able to do that in TL2016?

Yes/no answers are welcome, solutions even more so.

Cheers.

                                Jim