Description:
itstool --version              
/usr/bin/itstool:239: SyntaxWarning: invalid escape sequence '\s'
  if re.sub('\s+', ' ', text).strip() != '':
/usr/bin/itstool:337: SyntaxWarning: invalid escape sequence '\s'
  message = re.sub('\s+', ' ', message).strip()
/usr/bin/itstool:475: SyntaxWarning: invalid escape sequence '\s'
  return re.sub('\s+', ' ', self.locnote).strip()
/usr/bin/itstool:477: SyntaxWarning: invalid escape sequence '\s'
  return '(itstool) link: ' + re.sub('\s+', ' ', self.locnoteref).strip()
/usr/bin/itstool:891: SyntaxWarning: invalid escape sequence '\<'
  regex = re.compile('(.*) \<(.*)\>, (.*)')
/usr/bin/itstool:926: SyntaxWarning: invalid escape sequence '\s'
  if re.sub('\s+', '', prevtext) == '':
/usr/bin/itstool:1452: SyntaxWarning: invalid escape sequence '\.'
  _locale_pattern = re.compile('([a-zA-Z0-9-]+)(_[A-Za-z0-9]+)?(@[A-Za-z0-9]+)?(\.[A-Za-z0-9]+)?')
itstool 2.0.6

Having stderr output inside the returned command tricks the system to fail in detecting the version.
Ignoring stderr output looks fine to make it build properly
Author: Gianfranco Costamagna <locutusofborg@debian.org>
Last-Update: 2024-02-28

--- ardour-8.4.0+ds1.orig/wscript
+++ ardour-8.4.0+ds1/wscript
@@ -1003,7 +1003,7 @@ def configure(conf):
 
     # freedesktop translations needs itstool > 1.0.3 (-j option)
     if Options.options.freedesktop:
-        output = subprocess.Popen("itstool --version", shell=True, stderr=subprocess.STDOUT, stdout=subprocess.PIPE).communicate()[0].splitlines()
+        output = subprocess.Popen("itstool --version", shell=True, stderr=subprocess.DEVNULL, stdout=subprocess.PIPE).communicate()[0].splitlines()
         o = output[0].decode('utf-8')
         itstool = o.split(' ')[0]
         version = o.split(' ')[1].split('.')