Error compiling LibreOffice git (Xinerama not functional?)

[Clemens Eisserer]

Hi,

I am trying to diagnose some performance issues I am experiencing
running LO on Linux.
Compiling on Fedora-27 seems a little bit troublesome, as I:

* had to set libxslt and libexslt includes and libraries manually
* disable xrandr, despite headers and library installed, it aborted
with "not functional"

however, it seems the feature causing the latest issue can not be
simply disabled via a switch:

checking whether and how to use Xinerama... yes, with dynamic linking
checking X11/extensions/Xinerama.h usability... yes
checking X11/extensions/Xinerama.h presence... yes
checking for X11/extensions/Xinerama.h... yes
checking for XineramaIsActive in -lXinerama... no
configure: error: Xinerama not functional?

Any idea why LibreOffice thinks my Xinerama is not functional?
Can I disable it somehow?

Thank you and best regards, Clemens