[Development] headersclean configure option

[Lars Knoll]

Hi all,

Just something I keep stumbling over all the time: When you build Qt (at least as a developer-build), headersclean is enabled by default, adding ~40% to my build time locally. I usually try to disable it because of that, but keep forgetting about it.

Wouldn’t it make more sense to disable the flag by default (speeding up compiles for all our developers and users), but have a CI configuration that has it enabled so we don’t regress?

Cheers,
Lars