std: add struct field tags to untagged literals.

R=rsc, dsymonds, bsiegert, rogpeppe
CC=golang-dev
https://golang.org/cl/5619052
diff --git a/src/pkg/unicode/maketables.go b/src/pkg/unicode/maketables.go
index 393f8ea..ba39fec 100644
--- a/src/pkg/unicode/maketables.go
+++ b/src/pkg/unicode/maketables.go
@@ -652,7 +652,11 @@
 			s[j-1].Hi = r[i].hi
 		} else {
 			s = s[0 : j+1]
-			s[j] = unicode.Range32{uint32(r[i].lo), uint32(r[i].hi), 1}
+			s[j] = unicode.Range32{
+				Lo:     uint32(r[i].lo),
+				Hi:     uint32(r[i].hi),
+				Stride: 1,
+			}
 			j++
 		}
 	}