go: fix Xcode/CLT 8.3-related breakage.

Ref: https://github.com/golang/go/issues/19734.
Closes https://github.com/Homebrew/homebrew-core/issues/11739.

Formula/go.rb

@@ -1,6 +1,7 @@
 class Go < Formula
   desc "The Go programming language"
   homepage "https://golang.org"
+  revision 1
 
   stable do
     url "https://storage.googleapis.com/golang/go1.8.src.tar.gz"
@@ -13,6 +14,22 @@ class Go < Formula
       url "https://go.googlesource.com/tools.git",
           :branch => "release-branch.go#{go_version}"
     end
+
+    # Fixes for https://github.com/golang/go/issues/19734.
+    patch do
+      url "https://github.com/golang/go/commit/84192f27.patch"
+      sha256 "86badcb9318b5399de05520cfdd3c1abbc722a5f8cfcecc008815ff889230620"
+    end
+
+    patch do
+      url "https://github.com/golang/go/commit/3ca0d34f.patch"
+      sha256 "7c3a0ce6cf9bec784729bdca8f1798629690042c69cb4ee8c5e9cafaf73fc693"
+    end
+
+    patch do
+      url "https://github.com/golang/go/commit/2d004301.patch"
+      sha256 "2444a4191fd299b8a6e6eb6a671e7ca53005d0785b85343e5b512d4f093a069a"
+    end
   end
 
   bottle do