runtime: fix Plan 9 build

LGTM=0intro, aram
R=rsc, 0intro, aram
CC=golang-codereviews
https://golang.org/cl/109240044

diff --git a/src/pkg/runtime/os_plan9.c b/src/pkg/runtime/os_plan9.c
index 61f315a6c6c64add612975ef19afa241229daf8b..cf3480deac5687432d70b22fe0da2bcd241fd303 100644 (file)
--- a/src/pkg/runtime/os_plan9.c
+++ b/src/pkg/runtime/os_plan9.c
@@ -19,6 +19,7 @@ runtime·mpreinit(M *mp)
 {
        // Initialize stack and goroutine for note handling.
        mp->gsignal = runtime·malg(32*1024);
+       mp->gsignal->m = mp;
        mp->notesig = (int8*)runtime·malloc(ERRMAX*sizeof(int8));
 
        // Initialize stack for handling strings from the