back on reentrancy.... I know that with some of the libraries the extensions depend on are not reentrant (ie. also not thread safe). The imap library cclient comes to mind (unless something has changed recently) and I know gettext caches data in global structures (which would make me wonder). It occurs to me that we already have a list of extenions ( ./EXTENSIONS), what about adding an extra field to the listing? This field would be:
and would default to unknown. This would help those of us trying to use Apache2 to choose which extensions can be included based on the extension maintainers view of the safety of the code.