build: remove depdenency on GNU make

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/84920043

doc/articles/wiki/Makefile

-# Copyright 2010 The Go Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style
-# license that can be found in the LICENSE file.
-
-all: index.html
-
-CLEANFILES=get.bin final.bin a.out
-
-clean:
-	rm -f $(CLEANFILES)

doc/articles/wiki/test.bash

@@ -11,6 +11,8 @@ cleanup() {
 }
 trap cleanup 0 INT
 
+rm -f get.bin final.bin a.out
+
 # If called with -all, check that all code snippets compile.
 if [ "$1" == "-all" ]; then
 	for fn in *.go; do

src/run.bash

@@ -166,7 +166,6 @@ time ./run || exit 1
 
 [ "$GOARCH" == arm ] ||  # uses network, fails under QEMU
 (xcd ../doc/articles/wiki
-make clean || exit 1
 ./test.bash || exit 1
 ) || exit $?