[Libreoffice] Mac Build with lang=ALL

Thorsten,

So I tried a build with lang=ALL on mac.

indeed it is a dog. it took 15h20.
conservatively at least 13 hours of it were in helcontent2, mostly I/O
bound creating temp files and copying things around over and over.

based on profiling while this was running... I did another attempt at
building just helpcontent2 but with the follwing tweak:

export TMPDIR to a directory in a ramdisk and link unxmacxi.pro of
helpcontent2 to another directory in the same ramdisk (3.5GB needed)

the build of helcontent2 in these condition dropped to 26 minutes elapsed.

Note: that if you do not have enough memory to do that, you could at
least move the TMPDIR do a ramdisk. you don't need a big one (not sure
exactly how much, but I bet 500M should probably do)
there are some step in helpcontent2 that do a LOT of creation/delete on TMP.

Norbert