context: also consider path conflicts when clearing unknown files When clearing unknown files to remove path conflicts, also delete files that conflict with the target file's path. Differential Revision: https://phab.mercurial-scm.org/D785

merge: check for path conflicts when merging (issue5628) When merging, check for any path conflicts introduced by the manifest merge and rename the conflicting file to a safe name. Differential Revision: https://phab.mercurial-scm.org/D784

util: add safename function for generating safe names to rename to This function finds a name which does not clash with any other name in the manifest, and so can be used to safely rename a file. Differential Revision: https://phab.mercurial-scm.org/D783