Submitted upstream at https://github.com/Swordfish90/cool-retro-term/issues/692

--- a/qmltermwidget/lib/TerminalCharacterDecoder.cpp	1969-12-31 18:00:01.000000000 -0600
+++ b/qmltermwidget/lib/TerminalCharacterDecoder.cpp	2021-12-27 22:07:04.452256118 -0600
@@ -19,6 +19,8 @@
     02110-1301  USA.
 */
 
+#include <cwctype>
+
 // Own
 #include "TerminalCharacterDecoder.h"
 
 class='logo' rowspan='2'><a href='/'><img src='https://git.koszko.org/cgit-static/cgit.png' alt='cgit logo'/></a></td>
<td class='main'><a href='/'>index</a> : <a href='/guix/'>guix</a></td><td class='form'><form method='get'>
<input type='hidden' name='id' value='61a5305b395368816d8c594ae82bc794449a83c8'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=61a5305b395368816d8c594ae82bc794449a83c8'>refs</a><a class='active' href='/guix/log/gnu/packages/inkscape.scm'>log</a><a href='/guix/tree/gnu/packages/inkscape.scm?id=61a5305b395368816d8c594ae82bc794449a83c8'>tree</a><a href='/guix/commit/gnu/packages/inkscape.scm?id=61a5305b395368816d8c594ae82bc794449a83c8'>commit</a><a href='/guix/diff/gnu/packages/inkscape.scm?id=61a5305b395368816d8c594ae82bc794449a83c8'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/inkscape.scm'>
<input type='hidden' name='id' value='61a5305b395368816d8c594ae82bc794449a83c8'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=61a5305b395368816d8c594ae82bc794449a83c8'>root</a>/<a href='/guix/log/gnu?id=61a5305b395368816d8c594ae82bc794449a83c8'>gnu</a>/<a href='/guix/log/gnu/packages?id=61a5305b395368816d8c594ae82bc794449a83c8'>packages</a>/<a href='/guix/log/gnu/packages/inkscape.scm?id=61a5305b395368816d8c594ae82bc794449a83c8'>inkscape.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/inkscape.scm?id=61a5305b395368816d8c594ae82bc794449a83c8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-01-25 09:36:26 -0500'>2021-01-25</span></td><td><a href='/guix/commit/gnu/packages/inkscape.scm?id=f9bd4621dd92a9415276706b476b9bd2973411fa'>gnu: inkscape-1.0: Update to 1.0.2.</a><span class='msg-avail'>...</span></td><td>Michael Rohleder</td></tr>
<tr><td><span title='2020-10-26 15:53:04 +0000'>2020-10-26</span></td><td><a href='/guix/commit/gnu/packages/inkscape.scm?id=24b233d45c2a04a7a011397234b29fd5d7133110'>gnu: inkscape: Correct extension dependencies.</a><span class='msg-avail'>...</span></td><td>Ekaitz Zarraga</td></tr>
<tr><td><span title='2020-09-21 19:39:25 +0300'>2020-09-21</span></td><td><a href='/guix/commit/gnu/packages/inkscape.scm?id=17d30d1f6e63054f3c9006ae110009d99156e7c8'>gnu: inkscape-1.0: Update to 1.0.1.</a><span class='msg-avail'>...</span></td><td>Boris A. Dekshteyn</td></tr>