match: compose 'set:' pattern as matcher Baby step towards porting fileset to matcher composition. We can't use the exactmatcher since it would provide a computed set as exact paths. That's why we use the predicatematcher with fset.__contains__. This will be cleaned up later. The test change in test-glog.t means that the "set:copied()" pattern is no longer be processed as a slow path. That's because the fset is empty. This will also change in future patches.

pager.pager=p0 # $TESTTMP/sysrc:4
ui.editor=e1 # $TESTTMP/userrc:2

pager.pager=p2 # $PAGER
ui.editor=e1 # $TESTTMP/userrc:2