exim: apply patch for CVE-2017-1000369

Closes #15323.

Signed-off-by: ilovezfs <ilovezfs@icloud.com>

Formula/exim.rb

@@ -3,6 +3,7 @@ class Exim < Formula
   homepage "https://exim.org"
   url "https://ftp.exim.org/pub/exim/exim4/exim-4.89.tar.bz2"
   sha256 "912f2ee03c8dba06a3a4c0ee40522d367e1b65dc59e38dfcc1f5d9eecff51ab0"
+  revision 1
 
   bottle do
     sha256 "b76c1dc01d5ff622c16ddbaee4405b6738bd0a4443fa162714994bc055224014" => :sierra
@@ -17,6 +18,15 @@ class Exim < Formula
   depends_on "berkeley-db@4"
   depends_on "openssl"
 
+  # Patch applied upstream but doesn't apply cleanly from git.
+  # https://github.com/Exim/exim/commit/65e061b76867a9ea7aeeb535341b790b90ae6c21
+  patch do
+    url "https://mirrors.ocf.berkeley.edu/debian/pool/main/e/exim4/exim4_4.89-3.debian.tar.xz"
+    mirror "https://mirrorservice.org/sites/ftp.debian.org/debian/pool/main/e/exim4/exim4_4.89-3.debian.tar.xz"
+    sha256 "6440231912f6ead8097c94deb90524f9a0d1413447ba9ff3a734c4359e2aff3c"
+    apply "patches/79_CVE-2017-1000369.patch"
+  end
+
   def install
     cp "src/EDITME", "Local/Makefile"
     inreplace "Local/Makefile" do |s|