cmd/cgo: delete unused code

Change-Id: I6007cc6363e22ffa5f9a8f0441a642fd85127397
Reviewed-on: https://go-review.googlesource.com/c/go/+/435945
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
diff --git a/src/cmd/cgo/util.go b/src/cmd/cgo/util.go
index f2a5cd2..054cd6c 100644
--- a/src/cmd/cgo/util.go
+++ b/src/cmd/cgo/util.go
@@ -105,19 +105,6 @@
 	fmt.Fprintf(os.Stderr, "\n")
 }
 
-// isName reports whether s is a valid C identifier
-func isName(s string) bool {
-	for i, v := range s {
-		if v != '_' && (v < 'A' || v > 'Z') && (v < 'a' || v > 'z') && (v < '0' || v > '9') {
-			return false
-		}
-		if i == 0 && '0' <= v && v <= '9' {
-			return false
-		}
-	}
-	return s != ""
-}
-
 func creat(name string) *os.File {
 	f, err := os.Create(name)
 	if err != nil {
@@ -125,10 +112,3 @@
 	}
 	return f
 }
-
-func slashToUnderscore(c rune) rune {
-	if c == '/' || c == '\\' || c == ':' {
-		c = '_'
-	}
-	return c
-}