fix texlive/tex hang (mktexlsr)

To fix a very slow mktexlsr, look up the pathes in which your distribution put texfiles, and run for each of the directories
texhash <directory>
most probably running:
mktexlsr <directory>
also works
in archlinux the core tex files are in texlive-core

Here an example :

sudo texhash /usr/share/texmf-dist
sudo texhash /var/lib/texmf

as result a file will be created in /etc and mktexlsr should work now

Update: a missing /usr/share/texmf directory is maybe the cause for the bug in the first place (this directory is created e.g. by gnuplot (archlinux))