Use \PackageError directly

pdftex.def

@@ -25,13 +25,12 @@
   \RequirePackage{infwarerr}[2007/09/09]%
   \RequirePackage{ltxcmds}[2010/12/07]%
 
-\def\GPT@error{\PackageError{pdftex.def}}%
 \def\GPT@warn{\@PackageWarning{pdftex.def}}%
 \def\GPT@info{\@PackageInfoNoLine{pdftex.def}}%
 
 % Are we running under PDFTeX?
 \ltx@IfUndefined{pdftexversion}{%
-  \GPT@error{%
+  \PackageError{pdftex.def}{%
     Option `pdftex' requires pdfTeX,\MessageBreak
     but pdfTeX features are missing.\MessageBreak
     Loading of this driver file is aborted%
@@ -40,7 +39,7 @@
 
 % Ensure PDF mode
 \ifnum\pdfoutput<1 %
-  \GPT@error{%
+  \PackageError{pdftex.def}{%
     PDF mode expected, but DVI mode detected!\MessageBreak
     If you are using `latex', then call `pdflatex'.\MessageBreak
     Otherwise check and  correct the driver options.\MessageBreak
@@ -583,7 +582,7 @@ E     \else
     \let\Gin@ury\Gin@urx
     \ifGin@draft
     \else
-      \GPT@error{File `#2' not found}{%
+      \PackageError{pdftex.def}{File `#2' not found}{%
         Using draft setting for this image.\MessageBreak
         \@ehc
       }%
@@ -730,7 +729,7 @@ E     \else
   \else
     \GPT@IfFileExists{\GPT@print}{%
     }{%
-      \GPT@error{Print image `\GPT@print' not found}{%
+      \PackageError{pdftex.def}{Print image `\GPT@print' not found}{%
         The print version of the image is ignored.\MessageBreak
         \@ehc
       }%
@@ -1323,7 +1322,7 @@ E     \else
   % * Implementation of \providecommand is insufficient in miniltx.tex
   \@ifundefined{convertMPtoPDF}{%
     \newcommand{\convertMPtoPDF}[3]{%
-      \GPT@error{%
+      \PackageError{pdftex.def}{%
         Cannot convert ##1 from MPS to PDF.\MessageBreak
         The support file `supp-pdf.mkii' (supp-pdf.tex) is missing%
       }{%