runtime: remove unused getenv function

Change-Id: I49cda99f81b754e25fad1483de373f7d07d64808
Reviewed-on: https://go-review.googlesource.com/6452Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/env_plan9.go

@@ -6,15 +6,6 @@ package runtime
 
 import "unsafe"
 
-func getenv(s *byte) *byte {
-	val := gogetenv(gostringnocopy(s))
-	if val == "" {
-		return nil
-	}
-	// Strings found in environment are NUL-terminated.
-	return &bytes(val)[0]
-}
-
 var tracebackbuf [128]byte
 
 func gogetenv(key string) string {

src/runtime/env_posix.go

@@ -8,15 +8,6 @@ package runtime
 
 import "unsafe"
 
-func getenv(s *byte) *byte {
-	val := gogetenv(gostringnocopy(s))
-	if val == "" {
-		return nil
-	}
-	// Strings found in environment are NUL-terminated.
-	return &bytes(val)[0]
-}
-
 func gogetenv(key string) string {
 	env := environ()
 	if env == nil {