After the PDF.js changes from r294504, Source/WebKit/PlatformWPE.cmake is using GTK-specific variables.
Pull request: https://github.com/WebKit/WebKit/pull/825
Committed r294541 (250796@main): <https://commits.webkit.org/250796@main> Reviewed commits have been landed. Closing PR #825 and removing active labels.
Thanks for the fix.