Add an install target.

src/syncterm/GNUmakefile

@@ -22,10 +22,16 @@ LDFLAGS	+=	$(UIFC-MT_LDFLAGS) $(CIOLIB-MT_LDFLAGS) $(XPDEV-MT_LDFLAGS)
 
 vpath %.c ../sbbs3 ../smblib ../uifc ../guts
 
+INSTALL_EXE	?=	install
+
 $(SYNCTERM): $(EXEODIR) $(OBJS) $(BUILD_DEPENDS)
 	@echo Linking $@
 	${QUIET}$(CC) $(LDFLAGS) $(MT_LDFLAGS) $(OBJS) -o $@ $(UIFC-MT_LIBS) $(CIOLIB-MT_LIBS) $(XPDEV-MT_LIBS)
 
+install: $(SYNCTERM)
+	@echo Installing...
+	${INSTALL_EXE} ${SYNCTERM} ${PREFIX}/bin
+
 devel: tags cscope.out
 
 cscope.out: cscope.files