when explicitly either or both --with-xml-incdir and --with-xml-libdir are set skip xml2-config. Fixes issue 79835.
when explicitly either or both --with-xml-incdir and --with-xml-libdir
are set skip xml2-config. Fixes issue 79835.


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@38556 27541ba8-7e3a-0410-8455-c3a389f83636

bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT