The changes introduced in jcupitt@06802e4 assumes that the filesystem mounted on /tmp has the capability to handle the O_TMPFILE flag. This is not always the case, making vips fail when trying to create these temporary files.

Our use case was running vips in a docker container (docker for mac, nfs + overlayfs) but there might be others. I "fixed" this by removing the content from this commit from the code in my build (& applying a bit of C knowledge).

There should be a way to disable this behaviour, either at compile time or by adding a flag to the binary when running it. The later might be the more flexible option, the former the easier (but a bit brutal).