openssl: load zlib from an explicit path

Load zlib from an explicit path instead of relying on dyld's fallback
path, which is empty in a SIP context. This patch will be unnecessary
when we begin building openssl with no-comp to disable TLS compression.

This helps us load Python's "cryptography" library from system Python.

See https://langui.sh/2015/11/27/sip-and-dlopen for background.

Closes Homebrew/legacy-homebrew#47650.

Formula/openssl.rb

@@ -5,6 +5,7 @@ class Openssl < Formula
   mirror "https://dl.bintray.com/homebrew/mirror/openssl-1.0.2e.tar.gz"
   mirror "https://www.mirrorservice.org/sites/ftp.openssl.org/source/openssl-1.0.2e.tar.gz"
   sha256 "e23ccafdb75cfcde782da0151731aa2185195ac745eea3846133f2e05c0e0bff"
+  revision 1
 
   bottle do
     sha256 "a49cd2eaaeb44a8ae80bc57204a51890c807d2d13284e68b8c2ca17d1ec0366b" => :el_capitan
@@ -51,6 +52,14 @@ def configure_args; %W[
   end
 
   def install
+    # Load zlib from an explicit path instead of relying on dyld's fallback
+    # path, which is empty in a SIP context. This patch will be unnecessary
+    # when we begin building openssl with no-comp to disable TLS compression.
+    # https://langui.sh/2015/11/27/sip-and-dlopen
+    inreplace "crypto/comp/c_zlib.c",
+              'zlib_dso = DSO_load(NULL, "z", NULL, 0);',
+              'zlib_dso = DSO_load(NULL, "/usr/lib/libz.dylib", NULL, DSO_FLAG_NO_NAME_TRANSLATION);'
+
     if build.universal?
       ENV.permit_arch_flags
       archs = Hardware::CPU.universal_archs