patch-Makefile

--- Makefile.orig	2019-02-28 20:13:59 UTC
+++ Makefile
@@ -1,6 +1,6 @@
-CC = g++ -Wall -ggdb
-CC = g++ -pg
-CC = g++
+CXX ?= g++ -Wall -ggdb
+CXX ?= g++ -pg
+CXX ?= g++
 
 # default with OpenMP
 # with OpenMP
@@ -47,7 +47,7 @@ PROGS = cd-hit cd-hit-est cd-hit-2d cd-h
 CCFLAGS := $(CPPFLAGS) $(CCFLAGS) $(CXXFLAGS)
 
 .c++.o:
-	$(CC) $(CCFLAGS) -c $<
+	$(CXX) $(CCFLAGS) -c $<
 
 all: $(PROGS)
 
@@ -57,52 +57,53 @@ clean:
 # programs
 
 cd-hit: cdhit-common.o cdhit-utility.o cdhit.o
-	$(CC) $(CCFLAGS) cdhit.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit
+	$(CXX) $(CCFLAGS) cdhit.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit
 
 cd-hit-2d: cdhit-common.o cdhit-utility.o cdhit-2d.o
-	$(CC) $(CCFLAGS) cdhit-2d.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-2d
+	$(CXX) $(CCFLAGS) cdhit-2d.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-2d
 
 cd-hit-est: cdhit-common.o cdhit-utility.o cdhit-est.o
-	$(CC) $(CCFLAGS) cdhit-est.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-est
+	$(CXX) $(CCFLAGS) cdhit-est.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-est
 
 cd-hit-est-2d: cdhit-common.o cdhit-utility.o cdhit-est-2d.o
-	$(CC) $(CCFLAGS) cdhit-est-2d.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-est-2d
+	$(CXX) $(CCFLAGS) cdhit-est-2d.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-est-2d
 
 cd-hit-div: cdhit-common.o cdhit-utility.o cdhit-div.o
-	$(CC) $(CCFLAGS) cdhit-div.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-div
+	$(CXX) $(CCFLAGS) cdhit-div.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-div
 
 cd-hit-454: cdhit-common.o cdhit-utility.o cdhit-454.o
-	$(CC) $(CCFLAGS) cdhit-454.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-454
+	$(CXX) $(CCFLAGS) cdhit-454.o cdhit-common.o cdhit-utility.o $(LDFLAGS) cd-hit-454
 
 # objects
 cdhit-common.o: cdhit-common.c++ cdhit-common.h
-	$(CC) $(CCFLAGS) cdhit-common.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-common.c++ -c
 
 cdhit-utility.o: cdhit-utility.c++ cdhit-utility.h
-	$(CC) $(CCFLAGS) cdhit-utility.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-utility.c++ -c
 
 cdhit.o: cdhit.c++ cdhit-utility.h
-	$(CC) $(CCFLAGS) cdhit.c++ -c
+	$(CXX) $(CCFLAGS) cdhit.c++ -c
 
 cdhit-2d.o: cdhit-2d.c++ cdhit-utility.h
-	$(CC) $(CCFLAGS) cdhit-2d.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-2d.c++ -c
 
 cdhit-est.o: cdhit-est.c++ cdhit-utility.h
-	$(CC) $(CCFLAGS) cdhit-est.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-est.c++ -c
 
 cdhit-est-2d.o: cdhit-est-2d.c++ cdhit-utility.h
-	$(CC) $(CCFLAGS) cdhit-est-2d.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-est-2d.c++ -c
 
 cdhit-div.o: cdhit-div.c++ cdhit-common.h
-	$(CC) $(CCFLAGS) cdhit-div.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-div.c++ -c
 
 cdhit-454.o: cdhit-454.c++ cdhit-common.h
-	$(CC) $(CCFLAGS) cdhit-454.c++ -c
+	$(CXX) $(CCFLAGS) cdhit-454.c++ -c
 
-PREFIX ?= /usr/local/bin
+PREFIX ?= /usr/local
 
 install:
+	mkdir -p $(DESTDIR)$(PREFIX)/bin
 	for prog in $(PROGS); do \
-		install -m 0755 $$prog $(PREFIX); \
+		install -m 0755 $$prog $(DESTDIR)$(PREFIX)/bin; \
 	done
-	install -m 0755 *.pl $(PREFIX);
+	install -m 0755 *.pl $(DESTDIR)$(PREFIX)/bin