From cd777088d05beac3bb973fd6d41b2c89b64cbefc Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Wed, 1 May 2019 09:03:39 +0100
Subject: [PATCH] build_environment: tweak frozen string handling.

---
 Library/Homebrew/build_environment.rb | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/build_environment.rb b/Library/Homebrew/build_environment.rb
index ef91c825f0..ad0508d22a 100644
--- a/Library/Homebrew/build_environment.rb
+++ b/Library/Homebrew/build_environment.rb
@@ -56,11 +56,12 @@ module Homebrew
 
     keys.each do |key|
       value = env[key]
-      s = "#{key}: #{value}"
+      s = +"#{key}: #{value}"
       case key
       when "CC", "CXX", "LD"
-        s += " => #{Pathname.new(value).realpath}" if File.symlink?(value)
+        s << " => #{Pathname.new(value).realpath}" if File.symlink?(value)
       end
+      s.freeze
       f.puts s
     end
   end