bug#39482: 26.3; set-fontset-font with emacs charset does not work correctly

[Eli Zaretskii <eliz@gnu.org>]

> From: ynyaaa@gmail.com
> Cc: 39482@debbugs.gnu.org
> Date: Sat, 08 Feb 2020 19:50:48 +0900
> 
> > Are you using HarfBuzz?  I don't know if the installer installs the
> > HarfBuzz library by default.  If the library is not installed, Emacs
> > will fall back on Uniscribe, and you have the same problems as in
> > Emacs 26 again.  "C-u C-x =" on some character should tell you if
> > HarfBuzz or Uniscribe is being used.
> 
> 'C-u C-x =' on 'a' displays in *Help* buffer:
>               display: by this font (glyph code)
>     uniscribe:-outline-Courier New-normal-normal-normal-mono-13-*-*-*-c-*-iso8859-1 (#x44)
> 
> 'C-u C-x =' on '一' displays in *Help* buffer:
>               display: by this font (glyph code)
>     uniscribe:-outline-ＭＳ ゴシック-normal-normal-normal-mono-13-*-*-*-c-*-jisx0208*-* (#xB4D)

So HarfBuzz is not used.

> There are following DLLs in x86_64/bin directory.
> 2019/12/26  22:21         1,073,664 libharfbuzz-0.dll
> 2019/12/26  22:21            86,528 libharfbuzz-gobject-0.dll
> 2019/12/26  22:21            18,944 libharfbuzz-icu-0.dll
> 2019/12/26  22:21           545,280 libharfbuzz-subset-0.dll
> 
> 'M-x report-emacs-bug' displays following messages as initial contents.
> 
> In GNU Emacs 27.0.60 (build 1, x86_64-w64-mingw32)
>  of 2019-12-29 built on CIRROCUMULUS
> Repository revision: 21c3020fcec0a32122d2680a391864a75393031b
> Repository branch: emacs-27
> Windowing system distributor 'Microsoft Corp.', version 10.0.18363
> System Description: Microsoft Windows 10 Pro (v10.0.1909.18363.628)
> 
> Configured using:
>  'configure --without-dbus --host=x86_64-w64-mingw32
>  --without-compress-install -C 'CFLAGS=-O2 -static -g3''
> 
> Configured features:
> XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY W32NOTIFY ACL GNUTLS LIBXML2
> HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS PDUMPER LCMS2 GMP

Run the dependency walker (http://www.dependencywalker.com/) on
libharfbuzz-0.dll, and see if all of its dependencies are present.