cgo: don't overwrite p.Crefs

It's expected to be shared between all files so that all types are output.
Fixes bug reported on mailing list by Peter Froehlich.

R=rsc, phf
CC=golang-dev
https://golang.org/cl/183043

diff --git a/src/cmd/cgo/ast.go b/src/cmd/cgo/ast.go
index 76ff9ec653ae35016ebbbb713b1d8a6185cfce40..c78d8bb8e66deb44e841d68c73b39428dfb881fd 100644 (file)
--- a/src/cmd/cgo/ast.go
+++ b/src/cmd/cgo/ast.go
@@ -118,7 +118,9 @@ func openProg(name string, p *Prog) {
        }
 
        // Accumulate pointers to uses of C.x.
-       p.Crefs = make([]*Cref, 0, 8)
+       if p.Crefs == nil {
+               p.Crefs = make([]*Cref, 0, 8)
+       }
        walk(p.AST, p, "prog")
 }