m4_divert(-1)`'m4_dnl
m4_changecom(`##')
m4_define(`requirez',`m4_ifdef(`Got`$1'',`',`requirez1(`$1')')')
m4_define(`requirez1',`m4_define(`Got`$1'',1)'`requirez2($1)')
m4_define(`requirez2',`m4_divert(1)$1 m4_divert(-1) m4_include($1)')