diff --git a/GNUmakefile b/GNUmakefile
index 06c74b694..35f56d9cf 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -23,6 +23,7 @@ CARGOFLAGS ?=
 PREFIX ?= /usr/local
 DESTDIR ?=
 BINDIR ?= $(PREFIX)/bin
+DATAROOTDIR ?= $(PREFIX)/share
 
 INSTALLDIR_BIN=$(DESTDIR)$(BINDIR)
 
@@ -327,13 +328,13 @@ else
 		$(INSTALL) $(BUILDDIR)/$(prog) $(INSTALLDIR_BIN)/$(PROG_PREFIX)$(prog);)
 	$(if $(findstring test,$(INSTALLEES)), $(INSTALL) $(BUILDDIR)/test $(INSTALLDIR_BIN)/$(PROG_PREFIX)[)
 endif
-	mkdir -p $(DESTDIR)$(PREFIX)/share/zsh/site-functions
-	mkdir -p $(DESTDIR)$(PREFIX)/share/bash-completion/completions
-	mkdir -p $(DESTDIR)$(PREFIX)/share/fish/vendor_completions.d
+	mkdir -p $(DESTDIR)$(DATAROOTDIR)/zsh/site-functions
+	mkdir -p $(DESTDIR)$(DATAROOTDIR)/bash-completion/completions
+	mkdir -p $(DESTDIR)$(DATAROOTDIR)/fish/vendor_completions.d
 	$(foreach prog, $(INSTALLEES), \
-		$(BUILDDIR)/coreutils completion $(prog) zsh > $(DESTDIR)$(PREFIX)/share/zsh/site-functions/_$(PROG_PREFIX)$(prog); \
-		$(BUILDDIR)/coreutils completion $(prog) bash > $(DESTDIR)$(PREFIX)/share/bash-completion/completions/$(PROG_PREFIX)$(prog); \
-		$(BUILDDIR)/coreutils completion $(prog) fish > $(DESTDIR)$(PREFIX)/share/fish/vendor_completions.d/$(PROG_PREFIX)$(prog).fish; \
+		$(BUILDDIR)/coreutils completion $(prog) zsh > $(DESTDIR)$(DATAROOTDIR)/zsh/site-functions/_$(PROG_PREFIX)$(prog); \
+		$(BUILDDIR)/coreutils completion $(prog) bash > $(DESTDIR)$(DATAROOTDIR)/bash-completion/completions/$(PROG_PREFIX)$(prog); \
+		$(BUILDDIR)/coreutils completion $(prog) fish > $(DESTDIR)$(DATAROOTDIR)/fish/vendor_completions.d/$(PROG_PREFIX)$(prog).fish; \
 	)
 
 uninstall:
@@ -342,8 +343,8 @@ ifeq (${MULTICALL}, y)
 endif
 	rm -f $(addprefix $(INSTALLDIR_BIN)/$(PROG_PREFIX),$(PROGS))
 	rm -f $(INSTALLDIR_BIN)/$(PROG_PREFIX)[
-	rm -f $(addprefix $(DESTDIR)$(PREFIX)/share/zsh/site-functions/_$(PROG_PREFIX),$(PROGS))
-	rm -f $(addprefix $(DESTDIR)$(PREFIX)/share/bash-completion/completions/$(PROG_PREFIX),$(PROGS))
-	rm -f $(addprefix $(DESTDIR)$(PREFIX)/share/fish/vendor_completions.d/$(PROG_PREFIX),$(addsuffix .fish,$(PROGS)))
+	rm -f $(addprefix $(DESTDIR)$(DATAROOTDIR)/zsh/site-functions/_$(PROG_PREFIX),$(PROGS))
+	rm -f $(addprefix $(DESTDIR)$(DATAROOTDIR)/bash-completion/completions/$(PROG_PREFIX),$(PROGS))
+	rm -f $(addprefix $(DESTDIR)$(DATAROOTDIR)/fish/vendor_completions.d/$(PROG_PREFIX),$(addsuffix .fish,$(PROGS)))
 
 .PHONY: all build build-coreutils build-pkgs test distclean clean busytest install uninstall