[adblockplus repository] Update buildtools dependency to revision c4590ad32b6e

[trev]

Background

#2121 fixed a bug in the release automation, so this dependency update is required for a smooth release. Other changes imported by the dependency update:

• #1806, #1807, #1808 - Improvements to the ensure_dependencies.py script, addressing edge conditions not present for release builds.
• #1883, #1894, #1897, #2038 - Changes to image generation, no effect on the Firefox build as no images are being generated there.
• #2109 - A change to the way the metadata file is processed.
• #2171, #2216 - Changes to Chrome-specific code, no effect on the Firefox build.

What to change

Update dependency and re-run ensure_dependencies.py so that it can update itself.

Hints for testers

The Adblock Plus build produced after this change should be identical to the one before, with the build number being the only difference.

[trev]

Fixed: ​https://hg.adblockplus.org/adblockplus/rev/d1a11d338d09

I verified that the release builds were identical with an without this change, the development builds differed only by the build number.

[philll]

Made Firefox and Firefox mobile available as seperate platforms.

[modifaku]

spam