make: split the manpage / completions generation into their target

Thanks to this, it is easier to generate these files:
* make manpages
* make completions

GNUmakefile

@@ -337,7 +337,21 @@ clean:
 distclean: clean
 	$(CARGO) clean $(CARGOFLAGS) && $(CARGO) update $(CARGOFLAGS)
 
-install: build
+manpages: build-coreutils
+	mkdir -p $(BUILDDIR)/man/
+	$(foreach prog, $(INSTALLEES), \
+		$(BUILDDIR)/coreutils manpage $(prog) > $(BUILDDIR)/man/$(PROG_PREFIX)$(prog).1; \
+	)
+
+completions: build-coreutils
+	mkdir -p $(BUILDDIR)/completions/zsh $(BUILDDIR)/completions/bash $(BUILDDIR)/completions/fish
+	$(foreach prog, $(INSTALLEES), \
+		$(BUILDDIR)/coreutils completion $(prog) zsh > $(BUILDDIR)/completions/zsh/_$(PROG_PREFIX)$(prog); \
+		$(BUILDDIR)/coreutils completion $(prog) bash > $(BUILDDIR)/completions/bash/$(PROG_PREFIX)$(prog); \
+		$(BUILDDIR)/coreutils completion $(prog) fish > $(BUILDDIR)/completions/fish/$(PROG_PREFIX)$(prog).fish; \
+	)
+
+install: build manpages completions
 	mkdir -p $(INSTALLDIR_BIN)
 ifeq (${MULTICALL}, y)
 	$(INSTALL) $(BUILDDIR)/coreutils $(INSTALLDIR_BIN)/$(PROG_PREFIX)coreutils
@@ -349,15 +363,18 @@ else
 		$(INSTALL) $(BUILDDIR)/$(prog) $(INSTALLDIR_BIN)/$(PROG_PREFIX)$(prog);)
 	$(if $(findstring test,$(INSTALLEES)), $(INSTALL) $(BUILDDIR)/test $(INSTALLDIR_BIN)/$(PROG_PREFIX)[)
 endif
+	mkdir -p $(DESTDIR)$(DATAROOTDIR)/man/man1
+	$(foreach prog, $(INSTALLEES), \
+		$(INSTALL) $(BUILDDIR)/man/$(PROG_PREFIX)$(prog).1 $(DESTDIR)$(DATAROOTDIR)/man/man1/; \
+	)
+
 	mkdir -p $(DESTDIR)$(DATAROOTDIR)/zsh/site-functions
 	mkdir -p $(DESTDIR)$(DATAROOTDIR)/bash-completion/completions
 	mkdir -p $(DESTDIR)$(DATAROOTDIR)/fish/vendor_completions.d
-	mkdir -p $(DESTDIR)$(DATAROOTDIR)/man/man1
 	$(foreach prog, $(INSTALLEES), \
-		$(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; \
-		$(BUILDDIR)/coreutils manpage $(prog) > $(DESTDIR)$(DATAROOTDIR)/man/man1/$(PROG_PREFIX)$(prog).1; \
+		$(INSTALL) $(BUILDDIR)/completions/zsh/_$(PROG_PREFIX)$(prog) $(DESTDIR)$(DATAROOTDIR)/zsh/site-functions/; \
+		$(INSTALL) $(BUILDDIR)/completions/bash/$(PROG_PREFIX)$(prog) $(DESTDIR)$(DATAROOTDIR)/bash-completion/completions/; \
+		$(INSTALL) $(BUILDDIR)/completions/fish/$(PROG_PREFIX)$(prog).fish $(DESTDIR)$(DATAROOTDIR)/fish/vendor_completions.d/; \
 	)
 
 uninstall: