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(Windows) The use of macro ‘ZLIB_LIBS’ (which has not been documented for a long time) now requires an external ‘libz.a’ to be available (it is part of the ‘goodies’ used to compile Windows binary packages). It would be simplest to use ‘-lz’ directly.
‘loadNamespace()’ imposed undocumented restrictions on the ‘versionCheck’ parameter. (Reported by Geoff Lee.)