--- unzip60.orig/unix/Makefile	2009-01-18 23:41:18.000000000 +0100
+++ unzip60/unix/Makefile	2016-04-07 22:58:30.000000000 +0200
@@ -42,13 +42,13 @@
 # such as -DDOSWILD).
 
 # UnZip flags
-CC = cc#	try using "gcc" target rather than changing this (CC and LD
+CC ?= cc#	try using "gcc" target rather than changing this (CC and LD
 LD = $(CC)#	must match, else "unresolved symbol:  ___main" is possible)
 AS = as
 LOC = $(D_USE_BZ2) $(LOCAL_UNZIP)
 AF = $(LOC)
-CFLAGS = -O
-CF_NOOPT = -I. -I$(IZ_BZIP2) -DUNIX $(LOC)
+CFLAGS ?=
+CF_NOOPT = -I. -I$(IZ_BZIP2) -DUNIX $(CFLAGS)
 CF = $(CFLAGS) $(CF_NOOPT)
 LFLAGS1 =
 LF = -o unzip$E $(LFLAGS1)
@@ -545,7 +545,7 @@ generic:	flags	   # now try autoconfigur
 #	make $(MAKEF) unzips CF="${CF} `cat flags`"
 
 generic_gcc:
-	$(MAKE) $(MAKEF) generic CC=gcc IZ_BZIP2="$(IZ_BZIP2)"
+	$(MAKE) $(MAKEF) generic CC="$(CC)" IZ_BZIP2="$(IZ_BZIP2)"
 
 # extensions to perform SVR4 package-creation after compilation
 generic_pkg:	generic svr4package