Space and id normalization for included graphics

[mgkurtz]

For testing pdfjam’s pdfpages integration, I ran into a few inconsistencies regarding whitespace in output such as

[2

 <./source-1.pdf> <./source-1.pdf> <./source-1.pdf> <./source-1.pdf> <./source-1.pdf> <./source-1.pdf>] (a.aux)

Whether or not there is a space between the file names as well as whether there are line breaks varies depending on the tex engine and its version. Additionally the ids varied in output such as

<source-1.pdf, id=7, 597.508pt x 845.047pt>

These variations were quite nasty for ci/cd workflows running on a GitHub machine with an older texlive version than mine. By now, I fixed this by adding some own normalization machinery (just remove all whitespace after [1 until the ]) but thought that maybe I should bring this to your attention and ask whether you are interested in integrating any of this sort in l3build directly.

For reference: my normalization via `awk` and `sed`

<"$dir/a.log" awk 'BEGIN{s=0}
/^ *\[[0-9]/{ORS=""}
/]$/{ORS="\n"}
/] *\(/&&ORS=""{s=1}
/\)/&&s=1{s=0;ORS="\n"}
{print}
' | sed '/^ *\[[0-9]\+/s/ //g;/\.pdf,/s/id=[0-9]*/id=00/' >"$job.log"

If you are interested, I can rewrite this logic into Lua and create a PR.