diff --git a/Formula/zsh.rb b/Formula/zsh.rb
index 9213c9953a..7ef9f8d30e 100644
--- a/Formula/zsh.rb
+++ b/Formula/zsh.rb
@@ -32,12 +32,6 @@ class Zsh < Formula
   end
 
   def install
-    # Fix dyld: Symbol not found: _open_memstream
-    if MacOS.version == :sierra && MacOS::Xcode.installed? &&
-       MacOS::Xcode.version >= "9.0"
-      ENV["ac_cv_func_open_memstream"] = "no"
-    end
-
     system "Util/preconfig" if build.head?
 
     args = %W[