pkg: spelling tweaks, I-Z

also, a few miscellaneous fixes to files outside pkg

R=golang-dev, dsymonds, mikioh.mikioh, r
CC=golang-dev
https://golang.org/cl/4517116
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index f2f8dcd..2b2b34a 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -306,7 +306,7 @@
 
 /*
  * defined macros
- *    you need super-goru privilege
+ *    you need super-gopher-guru privilege
  *    to add this list.
  */
 #define	nelem(x)	(sizeof(x)/sizeof((x)[0]))