runtime: explain nacl closure failure

R=r, r2
CC=golang-dev
https://golang.org/cl/2889042

diff --git a/src/pkg/runtime/nacl/386/closure.c b/src/pkg/runtime/nacl/386/closure.c
index 6cab1eb5b5bd6ce4c7bb508e97f35cff3f636948..648efe6bdde9c2229c72b7a7d5d670b1c1ce6ba7 100644 (file)
--- a/src/pkg/runtime/nacl/386/closure.c
+++ b/src/pkg/runtime/nacl/386/closure.c
@@ -219,6 +219,8 @@ runtime·closure(int32 siz, byte *fn, byte *arg0)
                e = runtime·dyncode_copy(clos.ecode, clos.buf, ClosureChunk);
                if(e != 0) {
                        fd = 2;
+                       if(e == -22)
+                               runtime·throw("NaCl running with dyncode_copy disabled; export NACLDYNCODE=1 in your environment");
                        runtime·printf("dyncode_copy: error %d\n", e);
                        runtime·throw("dyncode_copy");
                }