It will be required by ICU 61 anyway, see
https://ssl.icu-project.org/repos/icu/trunk/icu4c/readme.html#RecBuild

Change-Id: Ia051e8e2aa64b0e32a7f16a2afebaef0e4ebf531
Reviewed-on: https://gerrit.libreoffice.org/46739Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>
(cherry picked from commit ad3b7c27)
Reviewed-on: https://gerrit.libreoffice.org/56713
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
(cherry picked from commit 63ebde21)