CygwinのXeLaTeXでBXjsclsを使うとfont-not-foundと言われる

環境

現象

test.tex
\documentclass[xelatex,ja=standard]{bxjsarticle}
\begin{document}\end{document}
コンパイル
$ xelatex test.tex
This is XeTeX, Version 3.14159265-2.6-0.99996 (TeX Live 2016/Cygwin) (preloaded format=xelatex)
 restricted \write18 enabled.
entering extended mode
(./test.tex
LaTeX2e <2016/03/31>
Babel <3.9r> and hyphenation patterns for 3 language(s) loaded.
(/usr/share/texmf-dist/tex/latex/bxjscls/bxjsarticle.cls
Document Class: bxjsarticle 2016/05/01 v1.1c BXJS document classes
(/usr/share/texmf-dist/tex/latex/tools/calc.sty)
(/usr/share/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texmf-dist/tex/latex/bxjscls/bxjscompat.sty)
(/usr/share/texmf-dist/tex/generic/oberdiek/ifpdf.sty)
(/usr/share/texmf-dist/tex/latex/geometry/geometry.sty
(/usr/share/texmf-dist/tex/generic/oberdiek/ifvtex.sty)
(/usr/share/texmf-dist/tex/generic/ifxetex/ifxetex.sty))
(/usr/share/texmf-dist/tex/latex/bxjscls/bxjsja-standard.def
(/usr/share/texmf-dist/tex/latex/bxjscls/bxjsja-minimal.def)
(/usr/share/texmf-dist/tex/latex/zxjatype/zxjatype.sty
(/usr/share/texmf-dist/tex/xelatex/xecjk/xeCJK.sty
(/usr/share/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/share/texmf-dist/tex/latex/l3kernel/expl3-code.tex)
(/usr/share/texmf-dist/tex/latex/l3kernel/l3xdvipdfmx.def))
(/usr/share/texmf-dist/tex/latex/l3packages/xtemplate/xtemplate.sty)
(/usr/share/texmf-dist/tex/latex/l3packages/xparse/xparse.sty)
(/usr/share/texmf-dist/tex/latex/l3packages/l3keys2e/l3keys2e.sty)
(/usr/share/texmf-dist/tex/latex/fontspec/fontspec.sty
(/usr/share/texmf-dist/tex/latex/fontspec/fontspec-xetex.sty
(/usr/share/texmf-dist/tex/latex/base/fontenc.sty
(/usr/share/texmf-dist/tex/latex/euenc/eu1enc.def)
(/usr/share/texmf-dist/tex/latex/euenc/eu1lmr.fd))
(/usr/share/texmf-dist/tex/xelatex/xunicode/xunicode.sty
(/usr/share/texmf-dist/tex/latex/tipa/t3enc.def
(/usr/share/texmf-dist/tex/latex/euenc/eu1lmss.fd))
(/usr/share/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/share/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/share/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/share/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/usr/share/texmf-dist/tex/xelatex/xetex-def/xetex.def
(/usr/share/texmf-dist/tex/generic/oberdiek/infwarerr.sty)
(/usr/share/texmf-dist/tex/generic/oberdiek/ltxcmds.sty)))))
(/usr/share/texmf-dist/tex/latex/fontspec/fontspec.cfg)))
(/usr/share/texmf-dist/tex/xelatex/xecjk/xunicode-addon.sty)
(/usr/share/texmf-dist/tex/xelatex/xunicode/xunicode.sty
*** Reloading Xunicode for encoding 'EU1' ***
) (/usr/share/texmf-dist/tex/xelatex/xecjk/xunicode-extra.def)
(/usr/share/texmf-dist/tex/xelatex/xecjk/xeCJK.cfg)))
kpathsea: Running mktextfm IPAexMincho/OT
/usr/share/texmf-dist/web2c/mktexnam: Could not map source abbreviation  for OT.
/usr/share/texmf-dist/web2c/mktexnam: Need to update ?
mktextfm: Running mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input OT
This is METAFONT, Version 2.7182818 (TeX Live 2016/Cygwin) (preloaded base=mf)


kpathsea: Running mktexmf OT
! I can't find file `OT'.
<*> \mode:=ljfour; mag:=1; nonstopmode; input OT
                                                
Please type another input file name
! Emergency stop.
<*> \mode:=ljfour; mag:=1; nonstopmode; input OT
                                                
Transcript written on mfput.log.
grep: OT.log: No such file or directory
mktextfm: `mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input OT' failed to make OT.tfm.
kpathsea: Appending font creation commands to missfont.log.


!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
! fontspec error: "font-not-found"
! 
! The font "IPAexMincho" cannot be found.
! 
! See the fontspec documentation for further information.
! 
! For immediate help type H <return>.
!...............................................  
                                                  
l.346 ...infont[BoldFont=IPAexGothic]{IPAexMincho}
                                                  
? X
No pages of output.
Transcript written on test.log.

対策

以下のファイルを作ったら解消した。詳細はよくわからない。fontconfigはインストールされてなくても良い?

/etc/fonts/local.conf
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<!-- local.conf file to configure local font access -->
<fontconfig>

<dir>/usr/share/texmf-dist/fonts/opentype</dir>
<dir>/usr/share/texmf-dist/fonts/truetype</dir>
<dir>/usr/share/texmf-local/fonts/opentype</dir>
<dir>/usr/share/texmf-local/fonts/truetype</dir>

</fontconfig>