diff -upr unrar.orig/makefile unrar/makefile
--- unrar.orig/makefile	2017-06-30 21:34:46.228703991 +0200
+++ unrar/makefile	2017-06-30 21:35:07.535424717 +0200
@@ -3,12 +3,12 @@
 
 # Linux using GCC
 CXX=c++
-CXXFLAGS=-O2
+CXXFLAGS?=-O2
 LIBFLAGS=-fPIC
 DEFINES=-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DRAR_SMP
 STRIP=strip
 AR=ar
-LDFLAGS=-pthread
+LDFLAGS+=-pthread
 DESTDIR=/usr
 
 # Linux using LCC
@@ -140,7 +140,7 @@ uninstall:	uninstall-unrar
 clean:
 	@rm -f *.o *.bak *~
 
-unrar:	clean $(OBJECTS) $(UNRAR_OBJ)
+unrar:	$(OBJECTS) $(UNRAR_OBJ)
 	@rm -f unrar
 	$(LINK) -o unrar $(LDFLAGS) $(OBJECTS) $(UNRAR_OBJ) $(LIBS)	
 	$(STRIP) unrar