Makefile: fix for cross-compilation

Probably-Signed-off-by: Dave Bender <bender@benegon.com>
[yann.morin.1998@free.fr: patch was made by Dave, but he
 forgot his SoB line, so I added it]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
diff -rupN cgic206/Makefile cgic206-br/Makefile
--- cgic206/Makefile	2014-03-16 18:17:11.000000000 -0400
+++ cgic206-br/Makefile	2015-01-16 11:18:03.714874000 -0500
@@ -1,15 +1,14 @@
-CFLAGS=-g -Wall
-CC=gcc
-AR=ar
-RANLIB=ranlib
 LIBS=-L./ -lcgic
 
 all: libcgic.a cgictest.cgi capture
 
 install: libcgic.a
-	cp libcgic.a /usr/local/lib
-	cp cgic.h /usr/local/include
-	@echo libcgic.a is in /usr/local/lib. cgic.h is in /usr/local/include.
+	cp libcgic.a $(PREFIX)/usr/lib
+	cp cgic.h $(PREFIX)/usr/include
+	@echo libcgic.a is in $(PREFIX)/usr/lib. cgic.h is in $(PREFIX)/usr/include.
+
+cgi.o: cgic.c cgic.h
+	$(CC) $(CFLAGS) cgic.c -o cgic.o
 
 libcgic.a: cgic.o cgic.h
 	rm -f libcgic.a
@@ -19,10 +18,10 @@ libcgic.a: cgic.o cgic.h
 #mingw32 and cygwin users: replace .cgi with .exe
 
 cgictest.cgi: cgictest.o libcgic.a
-	gcc cgictest.o -o cgictest.cgi ${LIBS}
+	$(CC) cgictest.o -o cgictest.cgi ${LIBS}
 
 capture: capture.o libcgic.a
-	gcc capture.o -o capture ${LIBS}
+	$(CC) capture.o -o capture ${LIBS}
 
 clean:
 	rm -f *.o *.a cgictest.cgi capture