Helper script:
  dirs=()
  for dir in $(find ./mate/24x24 -mindepth 1 -maxdepth 1 -type d); do
      directory=$(basename $dir)
      if [ -f "mate/22x22/$directory/Makefile.am" ]; \
      then
          cp mate/22x22/$directory/Makefile.am mate/24x24/$directory/Makefile.am
          sed -i -e 's/-w=22 -h=22/-w=24 -h=24/g' mate/24x24/$directory/Makefile.am
          dirs+=($directory)
      fi
  done
  ./autogen.sh
  for dir in ${dirs[@]}; do
      make -C mate/24x24/$dir clean-png-icons build-png-icons
  done

Change:
  -       @inkscape -z $^ --export-area=A:B:C:D -w=24 -h=24 -e=$@ 1> /dev/null
  +       @inkscape -z $^ --export-area=A-1:B-1:C+1:D+1 -w=24 -h=24 -e=$@ 1> /dev/null

$ inkscape -V
Inkscape 0.92.4 (unknown)
$ find . -type f -name Makefile.am -print0 | xargs -0 sed -i 's/ --convert-dpi-method=scale-document//g'
$ find . -type f -name Makefile.am -print0 | xargs -0 sed -i 's/ --convert-dpi-method=scale-viewbox//g'
$ find ./src -name *.svg -exec inkscape --convert-dpi-method=none --verb=FileVacuum --verb=FileSave --verb=FileQuit {} \;

clean & build:
  make -C mate clean-png-icons
  make -C mate build-png-icons