This option has been broken since I added it in bug #217989. It does properly configure the various JSC and bmalloc options, but doesn't get passed on from CMake to the actual build, so we wind up configuring a 4 KB max page size in PageBlock.h. Oops.
Created attachment 427759 [details] Patch
CC: Adrian, this would be a good backport for 2.32.
Committed r277015 (237331@main): <https://commits.webkit.org/237331@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 427759 [details].