Fix opkg compilation with ccache, thanks sn9

SVN-Revision: 12303

package/opkg/Makefile

@@ -53,7 +53,7 @@ endef
 
 define Build/Compile
 	$(MAKE) -C $(PKG_BUILD_DIR) \
-		CC=$(TARGET_CC) \
+		CC="$(TARGET_CC)" \
 		DESTDIR="$(PKG_INSTALL_DIR)" \
 		all install
 endef