--- Makefile.in.orig	2000-05-03 01:14:04.000000000 +0800
+++ Makefile.in	2014-06-30 23:46:37.906409781 +0800
@@ -27,7 +27,7 @@ SHELL = /bin/sh
 # for gzip because otherwise the load on the web server
 # grows without having big benefits.
 # COMPRESSION = -DCOMPRESSION=4
-COMPRESSION = -DCOMPRESSION=1
+COMPRESSION ?= -DCOMPRESSION=1
 
 # Dont change things beyond this line.
 TARGET          = @PROJECT_NAME@
@@ -59,7 +59,7 @@ srcdir          = @srcdir@
 docdir          = @DOCDIR@
 CPPFLAGS        = @CPPFLAGS@
 
-CFLAGS += -O2 -Wall
+CFLAGS ?= -O2 -Wall
 ALL_CFLAGS = $(CFLAGS) -I$(srcdir) -I. $(COMPRESSION) 
 
 all: $(TARGET)
@@ -70,24 +70,25 @@ $(TARGET): $(CONFIGIN) $(CONFIGS) $(LEXO
 $(LEXOUTPUT): $(CONFIGS) $(LEXSRCS) $(HDRS)
 	$(LEX) $(LEXSRCS)
 
-install: $(TARGET) install-doc
+install: $(TARGET)
 	@echo "Installing" $(TARGET) "to" $(bindir)
-	-mkdir -p $(bindir)
-	$(INSTALL_PROGRAM) $(TARGET) $(bindir)/$(TARGET)
+	-mkdir -p $(DESTDIR)$(bindir)
+	$(INSTALL_PROGRAM) $(TARGET) $(DESTDIR)$(bindir)/$(TARGET)
+	-mkdir -p $(DESTDIR)$(man1dir)
+	$(INSTALL_DATA) $(srcdir)/$(MANPAGE) $(DESTDIR)$(man1dir)/$(MANPAGE)
 
 install-strip: $(TARGET) install-doc
 	@echo "Installing" $(TARGET) "to" $(bindir)
-	-mkdir -p $(bindir)
-	$(INSTALL_PROGRAM) -s $(TARGET) $(bindir)/$(TARGET)
+	-mkdir -p $(DESTDIR)$(bindir)
+	$(INSTALL_PROGRAM) -s $(TARGET) $(DESTDIR)$(bindir)/$(TARGET)
 
 install-doc: 
-	-mkdir -p $(man1dir) $(docdir)
-	$(INSTALL_DATA) $(srcdir)/$(MANPAGE) $(man1dir)/$(MANPAGE)
-	$(INSTALL_DATA) $(srcdir)/AUTHORS $(docdir)/AUTHORS
-	$(INSTALL_DATA) $(srcdir)/COPYING $(docdir)/COPYING
-	$(INSTALL_DATA) $(srcdir)/NEWS $(docdir)/NEWS
-	$(INSTALL_DATA) $(srcdir)/README $(docdir)/README
-	$(INSTALL_DATA) $(srcdir)/$(LSM) $(docdir)/$(LSM)
+	-mkdir -p $(DESTDIR)$(docdir)
+	$(INSTALL_DATA) $(srcdir)/AUTHORS $(DESTDIR)$(docdir)/AUTHORS
+	$(INSTALL_DATA) $(srcdir)/COPYING $(DESTDIR)$(docdir)/COPYING
+	$(INSTALL_DATA) $(srcdir)/NEWS $(DESTDIR)$(docdir)/NEWS
+	$(INSTALL_DATA) $(srcdir)/README $(DESTDIR)$(docdir)/README
+	$(INSTALL_DATA) $(srcdir)/$(LSM) $(DESTDIR)$(docdir)/$(LSM)
 
 uninstall:
 	rm -f $(bindir)/$(TARGET)