GHC settings: always unescape escaped spaces

In #25204, it was noted that GHC didn't properly deal with having spaces in its executable path, as it would compute an invalid path for the C compiler.

The original fix in 31bf85ee used a trick: escape spaces before splitting up flags into a list. This fixed the behaviour with extra flags (e.g. -I), but forgot to also unescape for non-flags, e.g. for an executable path (such as the C compiler).

This commit rectifies this oversight by consistently unescaping the spaces that were introduced in order to split up argument lists.

added backport needed:9.10 backport needed:9.12 backport needed:9.6 backport needed:9.8 labels

@fendor You might want to take a look. Essentially, the problem is that we called unescapeArgs when dealing with flags, but for simple program paths like the path to the C compiler we did not unescape at all.

mentioned in issue #25204

Will take a look!

added 1 commit

• 17b7fd73 - GHC settings: always unescape escaped spaces

Compare with previous version

added 1 commit

• d8bf8976 - GHC settings: always unescape escaped spaces

Compare with previous version

marked this merge request as draft

added 1 commit

• c506a4e6 - GHC settings: always unescape escaped spaces

Compare with previous version

I have tested this MR and it does fix the bug. Unfortunately, I don't think the test currently triggers the bug.

marked this merge request as ready

added 1 commit

• 93c35dee - GHC settings: always unescape escaped spaces

Compare with previous version

added 1 commit

• 643fd9fb - GHC settings: always unescape escaped spaces

Compare with previous version

I have added a new test that checks that when the C compiler in the settings file has a space in it then compilation proceeds as expected.