--enable-icecream option mentions this in its documentation, but
it had been missing till now.

This option is also necessary when operating systems installs 
icecc wrappers in locations other than /usr/lib/icecc, /opt/icecream, 
which is what GCC_HOME gets set to by default with --enable-icecream.

Change-Id: Ib2b6ec010271467949e7ac9f1d01624cb360c5a5
Reviewed-on: https://gerrit.libreoffice.org/21551Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>