Not needed + breaks compilation on some platforms.
The compilation error was seen on 2.42.8, but also relevant
for 2.42.9 to not compile the test suite.
The option was added in 2.42.9:
801eef111d
```
[179/246] Generating tests/resources.c with a custom command
FAILED: tests/resources.c
/buildroot/output/host/bin/python3 /buildroot/output/build/host-gdk-pixbuf-2.42.8/build-aux/gen-resources.py --glib-compile-resources=/buildroot/output/host/bin/glib-compile-resources --pixdata=/buildroot/output/build/host-gdk-pixbuf-2.42.8/build/gdk-pixbuf/gdk-pixbuf-pixdata --loaders=/buildroot/output/build/host-gdk-pixbuf-2.42.8/build/gdk-pixbuf/loaders.cache --sourcedir=/buildroot/output/build/host-gdk-pixbuf-2.42.8/tests --source ../tests/resources.gresource.xml tests/resources.c
failed to load "/buildroot/output/build/host-gdk-pixbuf-2.42.8/tests/icc-profile.png": Couldn?t recognize the image file format for file ?/buildroot/output/build/host-gdk-pixbuf-2.42.8/tests/icc-profile.png?
../tests/resources.gresource.xml: Child process exited with code 1.
```
Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
f2dc971589