ld: grow dwarf includestack on demand.
Fixes #2241
while not breaking issue 1878 again.
R=rsc
CC=golang-dev
https://golang.org/cl/4988048
diff --git a/test/dwarf/linedirectives.go b/test/dwarf/linedirectives.go
new file mode 100755
index 0000000..68434f0
--- /dev/null
+++ b/test/dwarf/linedirectives.go
@@ -0,0 +1,83 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2011 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.
+
+//line foo/bar.y:4
+package main
+//line foo/bar.y:60
+func main() {
+//line foo/bar.y:297
+ f, l := 0, 0
+//line yacctab:1
+ f, l = 1, 1
+//line yaccpar:1
+ f, l = 2, 1
+//line foo/bar.y:82
+ f, l = 3, 82
+//line foo/bar.y:90
+ f, l = 3, 90
+//line foo/bar.y:92
+ f, l = 3, 92
+//line foo/bar.y:100
+ f, l = 3, 100
+//line foo/bar.y:104
+ l = 104
+//line foo/bar.y:112
+ l = 112
+//line foo/bar.y:117
+ l = 117
+//line foo/bar.y:121
+ l = 121
+//line foo/bar.y:125
+ l = 125
+//line foo/bar.y:133
+ l = 133
+//line foo/bar.y:146
+ l = 146
+//line foo/bar.y:148
+//line foo/bar.y:153
+//line foo/bar.y:155
+ l = 155
+//line foo/bar.y:160
+
+//line foo/bar.y:164
+//line foo/bar.y:173
+
+//line foo/bar.y:178
+//line foo/bar.y:180
+//line foo/bar.y:185
+//line foo/bar.y:195
+//line foo/bar.y:197
+//line foo/bar.y:202
+//line foo/bar.y:204
+//line foo/bar.y:208
+//line foo/bar.y:211
+//line foo/bar.y:213
+//line foo/bar.y:215
+//line foo/bar.y:217
+//line foo/bar.y:221
+//line foo/bar.y:229
+//line foo/bar.y:236
+//line foo/bar.y:238
+//line foo/bar.y:240
+//line foo/bar.y:244
+//line foo/bar.y:249
+//line foo/bar.y:253
+//line foo/bar.y:257
+//line foo/bar.y:262
+//line foo/bar.y:267
+//line foo/bar.y:272
+ if l == f {
+//line foo/bar.y:277
+ panic("aie!")
+//line foo/bar.y:281
+ }
+//line foo/bar.y:285
+ return
+//line foo/bar.y:288
+//line foo/bar.y:290
+}
+//line foo/bar.y:293
+//line foo/bar.y:295
