diff -upr unrar.orig/makefile unrar/makefile
--- unrar.orig/makefile	2018-03-11 17:33:12.697132381 +0100
+++ unrar/makefile	2018-03-11 17:33:48.763911497 +0100
@@ -2,13 +2,14 @@
 # Makefile for UNIX - unrar
 
 # Linux using GCC
-CXX=c++
-CXXFLAGS=-O2 -Wno-logical-op-parentheses -Wno-switch -Wno-dangling-else
+CXX?=c++
+CXXFLAGS?=-O2
+CXXFLAGS+=-Wno-logical-op-parentheses -Wno-switch -Wno-dangling-else
 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 +141,7 @@ 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