Add package-manager-friendly install targets and tunable variables

Makefile

@@ -1,8 +1,24 @@
 
-CC ?=	gcc
-CXX ?=	g++
+# Use ?= to allow overriding from the env or command-line, e.g.
+#
+#       make CXXFLAGS="-O3 -fPIC" install
+#
+# Package managers will override many of these variables automatically, so
+# this is aimed at making it easy to create packages (Debian packages,
+# FreeBSD ports, MacPorts, pkgsrc, etc.)
 
-all: multichoose multipermute
+CC ?=		cc
+CXX ?=		c++
+DESTDIR ?=	stage
+PREFIX ?=	/usr/local
+MKDIR ?=	mkdir
+INSTALL ?=	install -c
+STRIP ?=	strip
+AR ?=		ar
+
+BINS =	multichoose cmultichoose multipermute
+
+all: ${BINS}
 
 #multichoose_recursive: multichoose_recursive.cpp
 #	${CXX} multichoose_recursive.cpp -o multichoose_recursive
@@ -16,6 +32,15 @@ multipermute: multipermute.cpp multipermute.h
 cmultichoose: multichoose.c
 	${CC} multichoose.c -o cmultichoose
 
+install: all
+	${MKDIR} -p ${DESTDIR}${PREFIX}/bin
+	${MKDIR} -p ${DESTDIR}${PREFIX}/include/multichoose
+	${INSTALL} ${BINS} ${DESTDIR}${PREFIX}/bin
+	${INSTALL} *.py ${DESTDIR}${PREFIX}/bin
+	${INSTALL} *.h ${DESTDIR}${PREFIX}/include/multichoose
+
+install-strip: install
+	${STRIP} ${DESTDIR}${PREFIX}/bin/*e
+
 clean:
-	rm cmultichoose
-	rm multichoose
+	rm -rf ${BINS} ${DESTDIR}