--- Makefile.orig	2016-03-22 21:12:51 UTC
+++ Makefile
@@ -16,15 +16,16 @@
 #    number in tweak.h, or else the resulting binary won't match
 #    the version number on the archive.
 
-CC := gcc
-CFLAGS := -g -c -Wall $(XFLAGS)
-LINK := gcc
-LFLAGS :=
-LIBS := 
+CC ?= gcc
+CFLAGS ?= -g
+CFLAGS += -c -Wall $(XFLAGS)
+LINK ?= ${CC}
+LFLAGS ?=
+LIBS ?= 
 
-PREFIX=$(DESTDIR)/usr/local
-BINDIR=$(PREFIX)/bin
-MANDIR=$(PREFIX)/man/man1
+PREFIX?=/usr/local
+BINDIR?=$(PREFIX)/bin
+MANDIR?=$(PREFIX)/share/man/man1
 
 TWEAK := main.o keytab.o actions.o search.o rcfile.o buffer.o btree.o
 
@@ -63,10 +64,10 @@ release: tweak.1 btree.html
 	rm -rf reltmp
 
 install: tweak tweak.1
-	mkdir -p $(BINDIR)
-	install tweak $(BINDIR)/tweak
-	mkdir -p $(MANDIR)
-	install -m 0644 tweak.1 $(MANDIR)/tweak.1
+	mkdir -p $(DESTDIR)$(BINDIR)
+	install tweak $(DESTDIR)$(BINDIR)/tweak
+	mkdir -p $(DESTDIR)$(MANDIR)
+	install -m 0644 tweak.1 $(DESTDIR)$(MANDIR)/tweak.1
 
 clean:
 	rm -f *.o tweak tweak.1 btree.html