diff -up firefox-68.8.0/intl/icu_sources_data.py.icu-makefile firefox-68.8.0/intl/icu_sources_data.py

--- firefox-68.8.0/intl/icu_sources_data.py.icu-makefile	2020-05-11 17:00:03.642605718 +0200

+++ firefox-68.8.0/intl/icu_sources_data.py	2020-05-11 17:00:37.774642749 +0200

@@ -246,8 +246,7 @@ def update_data_file(topsrcdir):

     if not try_run(

             'icu-make',

             ['make',

-             '--jobs=%d' % multiprocessing.cpu_count(),

-             '--output-sync'],

+             '--jobs=1'],

             cwd=objdir):

         return False

     print('Copying ICU data file...')