New review comment by yopito on void-packages repository

https://github.com/void-linux/void-packages/pull/27349#discussion_r624544817

Comment:
I had a look on qt6-base and cmake and ccache. here my points:

"`-D-DQT_USE_CCACHE`" has no effect if ccache is enabled from xbps-src  : ccache will be used.
I think "`-DQT_USE_CCACHE=OFF`" might be a better idea (similar to other packages)

qt6-base build uses precompiled headers (pch) when working with automoc. ccache does not handle pch until some additional configuration (see https://ccache.dev/manual/4.2.1.html#_precompiled_headers).
 => so ccache is rather useless in this case: about 150/1160 "objects" are stored in ccache
workarounds:
* hope that packagers will enable pch support in ccache. IMHO, this support is somewhat imprecise, afraid of false positive
* disable use of pch for building qt6-base with "`-DBUILD_WITH_PCH=OFF`" : some overhead (not that much) on first build, but ccache efficiency after (about 70 minutes on 1st run, 6 minutes  then to build+package qt6-base). And no specific ccache settings is needed