https://bugs.gentoo.org/show_bug.cgi?id=260127
https://bugs.icu-project.org/trac/ticket/6934
https://bugs.icu-project.org/trac/changeset/28160

--- Makefile.in
+++ Makefile.in
@@ -219,8 +219,8 @@
 	$(INSTALL_SCRIPT) $(top_srcdir)/config/icu-config-top $@
 	chmod u+w $@
 	@echo "# Following from @platform_make_fragment@" >> $@
-	sed -f $(top_srcdir)/config/make2sh.sed < $(top_builddir)/config/Makefile.inc | grep -v '#M#' | uniq >> $@
-	sed -f $(top_srcdir)/config/make2sh.sed < @platform_make_fragment@ | grep -v '#M#' | uniq >> $@
+	LC_ALL=C sed -f $(top_srcdir)/config/make2sh.sed < $(top_builddir)/config/Makefile.inc | grep -v '#M#' | uniq >> $@
+	LC_ALL=C sed -f $(top_srcdir)/config/make2sh.sed < @platform_make_fragment@ | grep -v '#M#' | uniq >> $@
 	cat $(top_srcdir)/config/icu-config-bottom >> $@
 	echo "# Rebuilt on "`date` >> $@
 	chmod u-w $@