Rebase modified gdk-pixbuf package on top of 2.36.5-2+deb9u2

https://www.debian.org/security/2018/dsa-4088 => on my branch for #15148 (closed) I’ve seen our build system pull the update from Debian, which will fix security issues (good) but make the build non-reproducible (bad).

Feature Branch: bugfix/15177-rebase-gdk-pixbuf-on-deb9u2

Original created by @intrigeri on 15177 (Redmine)

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