relnotes: copy contents of "next" to "5.8" and clear "next" The same procedure as every year^Wcycle. Unlike previous cycles, I haven't actually recorded the copy because we don't want to propagate further changes in "next" (from the stable branch) to "5.8". Differential Revision: https://phab.mercurial-scm.org/D10500

dirstateguard: use mktemp-like functionality to generate the backup filenames Previously these were generated with names like: `dirstate.backup.commit.<memory address of dirstateguard>` This could cause problems if two hg commands ran at the same time that used the same memory address, (which is apparently not uncommon if chg is involved), as memory addresses are not unique across processes. This issue was reported in the post-review comments on http://phab.mercurial-scm.org/D9952. Differential Revision: https://phab.mercurial-scm.org/D10504