Because gst-build overrides the PKG_CONFIG_PATH in the sandbox, instead of aggregating to the one previously set, Cog fails to find the wpewebkit.pc file.
Created attachment 420836 [details] Patch
Committed r273234: <https://commits.webkit.org/r273234> All reviewed patches have been landed. Closing bug and clearing flags on attachment 420836 [details].
<rdar://problem/74589231>