remove use of PATH_MAX

helps gnu hurd, thanks Jay
sync
Merge remote-tracking branch 'origin/master' into gate
fix overlap detection
more polishing

and instrument stuff for vipsthumbnail
small polish
fix dist and build

was broken on old glibs
oops
sync
sync
Merge remote-tracking branch 'origin/7.36'
fix im_benchmark()
remove repack code from affine

just done in compat wrapper now