naiveproxy: fix with python 2.x installed building

naiveproxy/Makefile

@@ -122,7 +122,7 @@ define Build/Configure
 		. ../init_env.sh "$(ARCH)" $(CPU_TYPE) $(CPU_SUBTYPE) "$(TOOLCHAIN_DIR)" ; \
 		export naive_flags+=" $$$${naive_ccache_flags}" ; \
 		mkdir -p "out" ; \
-		./gn/out/gn gen "out/Release" --args="$$$${naive_flags}" --script-executable="$(PYTHON)" ; \
+		./gn/out/gn gen "out/Release" --args="$$$${naive_flags}" --script-executable="python3" ; \
 		popd ; \
 	)
 endef