infra: pepper some GNU on top of Makefile

Makefile

@@ -13,6 +13,15 @@ CSC_FLAGS += -K prefix -static
 # -c: Stop after compilation to object files. This one is obvious.
 CHICKEN_INSTALL = chicken-install
 
+# GNU directory variables. Command line overrides, e.g.
+#   make prefix=$(HOME)/.local install
+#   make DESTDIR=/tmp/stage prefix=/usr install
+prefix = /usr/local
+exec_prefix = $(prefix)
+bindir = $(exec_prefix)/bin
+INSTALL = install
+INSTALL_PROGRAM = $(INSTALL)
+
 MODULE_FLAGS = -emit-all-import-libraries -module-registration -c
 
 # Order matters, since module check correctness on compilation
@@ -87,6 +96,18 @@ check-exit-code: sexc
 run-tests: sexc sex-tests sextest
 	./sex-tests && ./sextest --sexc=./sexc $(SEX_TEST_PROGRAMS:%=./tests/sex-programs/%.sex) && $(MAKE) check-modules && $(MAKE) check-exit-code
 
+install: all installdirs
+	$(INSTALL_PROGRAM) sexc $(DESTDIR)$(bindir)/sexc
+
+install-strip:
+	$(MAKE) INSTALL_PROGRAM='$(INSTALL_PROGRAM) -s' install
+
+installdirs:
+	$(INSTALL) -d $(DESTDIR)$(bindir)
+
+uninstall:
+	rm -f $(DESTDIR)$(bindir)/sexc
+
 run-tests: sex-tests
 	./sex-tests
 
@@ -104,4 +125,8 @@ clean:
 	rm -f sexc sex-tests sextest
 	$(MAKE) -C ./tests/modules clean
 
-.PHONY: clean depclean deps run-tests sex-tests sextest check-modules check-exit-code
+deps-clean:
+	rm -rf $(EGGS_DIR)
+
+.PHONY: all check run-tests check-modules check-exit-code install install-strip installdirs
+	uninstall deps deps-update clean depsclean sex-tests sextest