cmd/dist: fix bug in bsubst

R=golang-dev, r, dsymonds, akumar
CC=golang-dev
https://golang.org/cl/5624054

diff --git a/src/cmd/dist/buf.c b/src/cmd/dist/buf.c
old mode 100644 (file)
new mode 100755 (executable)
index c990c8a..45fb195
--- a/src/cmd/dist/buf.c
+++ b/src/cmd/dist/buf.c
@@ -115,8 +115,11 @@ bsubst(Buf *b, char *x, char *y)
                if(p == nil)
                        break;
                if(nx != ny) {
-                       if(nx < ny)
+                       if(nx < ny) {
+                               pos = p - b->p;
                                bgrow(b, ny-nx);
+                               p = b->p + pos;
+                       }
                        xmemmove(p+ny, p+nx, (b->p+b->len)-(p+nx));
                }
                xmemmove(p, y, ny);