Looking at how we build LibreOffice in Fedora, there are some features missing compared to upstream.
I’d like to start a discussion whether or not pulling in those.
@limb @sharkcz @sbergmann @decathorpe
--disable-coinmp
We actually build without support for the CoinMP based linear equation solver. This is really easy to “fix”, we just need to pull in a BR on coin-or-CoinMP-devel and tadah.
However the resultant RPMs will also bring in ~105MB of new dependencies when installing on the end system (I suppose only when installing libreoffice-calc, but I have not tried).
Considered that the coinmp solver is a rather specific feature which could bring unknown performance improvement over the standard linear solver, I wonder if it is worthy to enable the feature or not.
--disable-pdfium
--disable-skia
These are related, as by a first glance enabling pdfium requires skia.
I don’t think we can enable those without bundling the components as upstream does. Both skia and pdfium uses the same build process of chromium and looking to Fedora chromium specfile I see it uses a bundled skia (no pdfium, though).
Maybe, if Chromium folks are interested, we could join forces, but I don’t know how hard could be. Volunteers welcome 
--without-system-dragonbox
We currently bundle dragonbox, will be fixed when the package review is approved.
--without-system-libfixmath
Not sure it is worthy to unbundle. Google’s upstream is long archived. There’s a fork on github which says it is not actively maintained.
--without-system-hsqldb
We use a bundled, old version of hsqldb. The specfile says
#Unfortunately later versions of hsqldb changed the file format, so if we use a later version we lose
#backwards compatability.
The bundled hsqldb is version 1.8.0 which is more than 10 years old… shall we try switching to system’s hsqldb 2.4.0, maybe with the next “major” (i.e. 7.7) version bump (possibly on F40)?