diff -up firefox-68.0/build/autoconf/icu.m4.icu firefox-68.0/build/autoconf/icu.m4
--- firefox-68.0/build/autoconf/icu.m4.icu	2019-06-25 21:25:25.394425654 +0200
+++ firefox-68.0/build/autoconf/icu.m4	2019-06-25 21:26:23.544210474 +0200
@@ -78,7 +78,7 @@ if test -n "$USE_ICU"; then
     # TODO: the l is actually endian-dependent
     # We could make this set as 'l' or 'b' for little or big, respectively,
     # but we'd need to check in a big-endian version of the file.
-    ICU_DATA_FILE="icudt${version}l.dat"
+    ICU_DATA_FILE="icudt${version}b.dat"
 fi
 
 AC_SUBST(MOZ_ICU_VERSION)