amsmath.sty + pdfx.styで\hat{\hat{f}}等がエラーになる問題へのpatch（いきおい）

pdfx-mathaccent.patch

--- /usr/local/texlive/2019/texmf-dist/tex/latex/pdfx/pdfx.sty  2019-03-12 07:01:25.000000000 +0900
+++ ./pdfx.sty  2019-05-07 11:15:38.000000000 +0900
@@ -31,7 +31,7 @@
 }{}%
 \NeedsTeXFormat{LaTeX2e}
 \ProvidesPackage{pdfx}
-  [2019/02/27 v1.6.3 PDF/X and PDF/A support (CVR/HTH/RRM/PS)]
+  [2019/05/07 v1.6.3.1-test PDF/X and PDF/A support (CVR/HTH/RRM/PS)]
 
 \newif\ifpdfx@noBOM \pdfx@noBOMfalse   % use a BOM in the XMP packet
 \newif\ifpdfx@x \pdfx@xfalse   % PDF/X mode
@@ -2474,6 +2474,29 @@
  \spacefactor\accent@spacefactor
 }
 %% same for named accents in math-mode
+\@ifpackageloaded{amsmath}{%
+  \def\pdfx@macc@a#1#2{%
+    \begingroup
+    \let\macc@style#1\relax
+    \def\macc@palette##1{##1\macc@style}%
+    \advance\macc@depth\m@ne
+    \ifnum\macc@depth=\z@
+      \gdef\macc@nucleus{\phantom{#2}}%
+      \setbox\z@\hbox{$#1#2\@empty{}\macc@skewchar$}%
+      \setbox\tw@\hbox{$#1#2\@empty\macc@skewchar$}%
+      \dimen@\tw@\wd\tw@ \advance\dimen@-\tw@\wd\z@
+      \xdef\macc@kerna{\the\dimen@\relax}%
+      \setbox4\hbox{$#1#2\acc@check\@empty$}%
+      \global\setbox\@ne\hbox to\wd4{}%
+      \ht\@ne\ht4 \dp\@ne\dp4
+      \xdef\macc@kernb{\the\wd4\relax}%
+      \mathaccent\macc@code{\box\@ne\kern\macc@kerna}%
+    \else
+      \mathaccent\macc@code{\let\macc@adjust\@empty #1#2\@empty}%
+      \macc@adjust
+    \fi
+    \endgroup
+  }}\relax
 \def\pdfx@mathaccentV#1#2#3#4#5{%
  #5{\mathsurround=\z@\relax
   \everymath{}%
@@ -2483,12 +2506,13 @@
    {\setbox\z@\hbox{$\scriptstyle #5$}\kern-\wd\z@}%
    {\setbox\z@\hbox{$\scriptscriptstyle #5$}\kern-\wd\z@}%
  }%
- \AMS@mathaccentV{#1}{#2}{#3}{#4}{\phantom{#5}}%
+ \AMS@mathaccentV{#1}{#2}{#3}{#4}{#5}%
 }
 \AtBeginDocument{%
  \@ifpackageloaded{amsmath}{%
   \let\AMS@mathaccentV\mathaccentV
-  \let\mathaccentV\pdfx@mathaccentV}%
+  \let\mathaccentV\pdfx@mathaccentV
+  \let\macc@a\pdfx@macc@a}%
 }%
 
 %% How to support XeTeX here ?