diff --git a/Library/Homebrew/extend/os/mac/extend/ENV/super.rb b/Library/Homebrew/extend/os/mac/extend/ENV/super.rb
index 0f6bdb8343..5872c2264f 100644
--- a/Library/Homebrew/extend/os/mac/extend/ENV/super.rb
+++ b/Library/Homebrew/extend/os/mac/extend/ENV/super.rb
@@ -99,8 +99,9 @@ module Superenv
     # Filter out symbols known not to be defined since GNU Autotools can't
     # reliably figure this out with Xcode 8 and above.
     if MacOS.version == "10.12" && MacOS::Xcode.installed? && MacOS::Xcode.version >= "9.0"
-      ENV["ac_cv_func_futimens"] = "no"
-      ENV["ac_cv_func_utimensat"] = "no"
+      %w[fmemopen futimens open_memstream utimensat].each do |s|
+        ENV["ac_cv_func_#{s}"] = "no"
+      end
     elsif MacOS.version == "10.11" && MacOS::Xcode.installed? && MacOS::Xcode.version >= "8.0"
       %w[basename_r clock_getres clock_gettime clock_settime dirname_r
          getentropy mkostemp mkostemps timingsafe_bcmp].each do |s|