Test:
  $ ./autogen.sh prefix=/usr && make && sudo make install
  $ ls /usr/share/icons/hicolor/24x24/apps/mate-disk-usage-analyzer.png

TEST on Fedora:
inkscape, librsvg2-tools package are not installed on system: The user can build, install and distribute the package:

  $ sudo dnf remove inkscape librsvg2-tools -y
  $ ./configure --prefix=/usr
  $ make
  $ sudo make install
  $ make distcheck

logview/data/icons:

Can not run build-png-icons target if inkscape package is not installed on system:

  $ make -C logview/data/icons clean-png-icons
make: Entering directory '/home/robert/devel/mate-utils/logview/data/icons'
rm -f hicolor_apps_16x16_mate-system-log.png hicolor_apps_22x22_mate-system-log.png hicolor_apps_32x32_mate-system-log.png hicolor_apps_48x48_mate-system-log.png hicolor_apps_256x256_mate-system-log.png
make: Leaving directory '/home/robert/devel/mate-utils/logview/data/icons'
  $ make -C logview/data/icons build-png-icons
make: Entering directory '/home/robert/devel/mate-utils/logview/data/icons'
make: *** No rule to make target 'hicolor_apps_16x16_mate-system-log.png', needed by 'build-png-icons'.  Stop.
make: Leaving directory '/home/robert/devel/mate-utils/logview/data/icons'

Can run build-png-icons target if inkscape package is installed on system:

  $ sudo dnf install inkscape -y
  $ ./configure --prefix=/usr
  $ make -C logview/data/icons build-png-icons
make: Entering directory '/home/robert/devel/mate-utils/logview/data/icons'
Background RRGGBBAA: ffffff00 Area 303:65:319:81 exported to 16 x 16 pixels (96 dpi) Bitmap saved as: hicolor_apps_16x16_mate-system-log.png
Background RRGGBBAA: ffffff00 Area 303:101:325:123 exported to 22 x 22 pixels (96 dpi) Bitmap saved as: hicolor_apps_22x22_mate-system-log.png
Background RRGGBBAA: ffffff00 Area 304:142:336:174 exported to 32 x 32 pixels (96 dpi) Bitmap saved as: hicolor_apps_32x32_mate-system-log.png
Background RRGGBBAA: ffffff00 Area 296:202:344:250 exported to 48 x 48 pixels (96 dpi) Bitmap saved as: hicolor_apps_48x48_mate-system-log.png
Background RRGGBBAA: ffffff00 Area 33:11:289:267 exported to 256 x 256 pixels (96 dpi) Bitmap saved as: hicolor_apps_256x256_mate-system-log.png
make: Nothing to be done for 'build-png-icons'.
make: Leaving directory '/home/robert/devel/mate-utils/logview/data/icons'

baobab/pixmaps:

Can not run build-png-icons target if librsvg2-tools package is not installed on system:

  $ make -C baobab/pixmaps clean-png-icons
make: Entering directory '/home/robert/devel/mate-utils/baobab/pixmaps'
rm -f hicolor_apps_16x16_mate-disk-usage-analyzer.png hicolor_apps_22x22_mate-disk-usage-analyzer.png hicolor_apps_32x32_mate-disk-usage-analyzer.png hicolor_apps_48x48_mate-disk-usage-analyzer.png hicolor_apps_128x128_mate-disk-usage-analyzer.png
make: Leaving directory '/home/robert/devel/mate-utils/baobab/pixmaps'
  $ make -C baobab/pixmaps build-png-icons
make: Entering directory '/home/robert/devel/mate-utils/baobab/pixmaps'
make: *** No rule to make target 'hicolor_apps_16x16_mate-disk-usage-analyzer.png', needed by 'build-png-icons'.  Stop.
make: Leaving directory '/home/robert/devel/mate-utils/baobab/pixmaps'

Can run build-png-icons target if librsvg2-tools package is installed on system:

  $ sudo dnf install -y librsvg2-tools
  $ ./configure --prefix=/usr
  $ make -C baobab/pixmaps build-png-icons
make: Entering directory '/home/robert/devel/mate-utils/baobab/pixmaps'
/usr/bin/rsvg-convert -w 16 -h 16 hicolor_apps_scalable_mate-disk-usage-analyzer.svg -o hicolor_apps_16x16_mate-disk-usage-analyzer.png
/usr/bin/rsvg-convert -w 22 -h 22 hicolor_apps_scalable_mate-disk-usage-analyzer.svg -o hicolor_apps_22x22_mate-disk-usage-analyzer.png
/usr/bin/rsvg-convert -w 32 -h 32 hicolor_apps_scalable_mate-disk-usage-analyzer.svg -o hicolor_apps_32x32_mate-disk-usage-analyzer.png
/usr/bin/rsvg-convert -w 48 -h 48 hicolor_apps_scalable_mate-disk-usage-analyzer.svg -o hicolor_apps_48x48_mate-disk-usage-analyzer.png
/usr/bin/rsvg-convert -w 128 -h 128 hicolor_apps_scalable_mate-disk-usage-analyzer.svg -o hicolor_apps_128x128_mate-disk-usage-analyzer.png
make: Leaving directory '/home/robert/devel/mate-utils/baobab/pixmaps'

Closes #223

In addition, it removes unnecessary function type casts like:
  (GDestroyNotify) g_object_unref
  (GDestroyNotify) g_free

To detect the memory leak using valgrind:

export CFLAGS="-Og -g -fno-omit-frame-pointer -fPIE -pie"
export CXXFLAGS="-Og -g -fno-omit-frame-pointer -fPIE -pie"
./autogen.sh --prefix=/usr
make clean
make
sudo make install
valgrind --tool=memcheck --undef-value-errors=no --leak-check=full --log-file="report.txt" /usr/bin/mate-disk-usage-analyzer

report.txt content:

==16061== 6 bytes in 1 blocks are definitely lost in loss record 174 of 14,390
==16061==    at 0x483880B: malloc (vg_replace_malloc.c:309)
==16061==    by 0x56B10D7: g_malloc (gmem.c:99)
==16061==    by 0x56CAAEE: g_strdup (gstrfuncs.c:363)
==16061==    by 0x56E3743: g_variant_dup_string (gvariant.c:1533)
==16061==    by 0x5509DE6: g_settings_get_string (gsettings.c:1795)
==16061==    by 0x115664: initialize_charts (baobab.c:1185)
==16061==    by 0x11640C: main (baobab.c:1307)

  PNG icons are created if they are not present in icon folder.

  To remove png icons:
    make -C baobab/pixmaps clean-png-icons
    make -C logview/data/icons clean-png-icons

  To build png icons:
    make -C baobab/pixmaps build-png-icons
    make -C logview/data/icons build-png-icons

This removes baobab/pixmaps/shot.png file, use applets-screenshooter
named icon (used in mate-screenshot).