Nix: Patch subversion on Darwin

Things fail when running "import svn.client" due to a missing symbol.

pkgs/subversion-1.9.4-darwin.patch

@@ -0,0 +1,63 b''
+diff -rup subversion-1.9.4-orig/subversion/include/svn_auth.h subversion-1.9.4/subversion/include/svn_auth.h
+--- subversion-1.9.4-orig/subversion/include/svn_auth.h	2015-02-13 12:17:40.000000000 +0100
++++ subversion-1.9.4/subversion/include/svn_auth.h	2016-09-21 12:55:27.000000000 +0200
+@@ -943,7 +943,7 @@ svn_auth_get_windows_ssl_server_trust_pr
+ 
+ #endif /* WIN32 && !__MINGW32__ || DOXYGEN */
+ 
+-#if defined(DARWIN) || defined(DOXYGEN)
++#if defined(SVN_HAVE_KEYCHAIN_SERVICES) || defined(DOXYGEN)
+ /**
+  * Set @a *provider to an authentication provider of type @c
+  * svn_auth_cred_simple_t that gets/sets information from the user's
+@@ -984,7 +984,7 @@ void
+ svn_auth_get_keychain_ssl_client_cert_pw_provider(
+   svn_auth_provider_object_t **provider,
+   apr_pool_t *pool);
+-#endif /* DARWIN || DOXYGEN */
++#endif /* SVN_HAVE_KEYCHAIN_SERVICES || DOXYGEN */
+ 
+ /* Note that the gnome keyring unlock prompt related items below must be
+  * declared for all platforms in order to allow SWIG interfaces to be
+diff -rup subversion-1.9.4-orig/subversion/libsvn_subr/auth.h subversion-1.9.4/subversion/libsvn_subr/auth.h
+--- subversion-1.9.4-orig/subversion/libsvn_subr/auth.h	2015-08-27 06:00:31.000000000 +0200
++++ subversion-1.9.4/subversion/libsvn_subr/auth.h	2016-09-21 12:56:20.000000000 +0200
+@@ -103,7 +103,7 @@ svn_auth__get_windows_ssl_server_trust_p
+   apr_pool_t *pool);
+ #endif /* WIN32 && !__MINGW32__ || DOXYGEN */
+ 
+-#if defined(DARWIN) || defined(DOXYGEN)
++#if defined(SVN_HAVE_KEYCHAIN_SERVICES) || defined(DOXYGEN)
+ /**
+  * Set @a *provider to an authentication provider of type @c
+  * svn_auth_cred_simple_t that gets/sets information from the user's
+@@ -134,7 +134,7 @@ void
+ svn_auth__get_keychain_ssl_client_cert_pw_provider(
+   svn_auth_provider_object_t **provider,
+   apr_pool_t *pool);
+-#endif /* DARWIN || DOXYGEN */
++#endif /* SVN_HAVE_KEYCHAIN_SERVICES || DOXYGEN */
+ 
+ #if !defined(WIN32) || defined(DOXYGEN)
+ /**
+diff -rup subversion-1.9.4-orig/subversion/libsvn_subr/deprecated.c subversion-1.9.4/subversion/libsvn_subr/deprecated.c
+--- subversion-1.9.4-orig/subversion/libsvn_subr/deprecated.c	2015-08-27 06:00:31.000000000 +0200
++++ subversion-1.9.4/subversion/libsvn_subr/deprecated.c	2016-09-21 12:57:08.000000000 +0200
+@@ -1479,7 +1479,7 @@ svn_auth_get_windows_ssl_server_trust_pr
+ #endif /* WIN32 && !__MINGW32__ */
+ 
+ /*** From macos_keychain.c ***/
+-#if defined(DARWIN)
++#if defined(SVN_HAVE_KEYCHAIN_SERVICES)
+ void
+ svn_auth_get_keychain_simple_provider(svn_auth_provider_object_t **provider,
+                                       apr_pool_t *pool)
+@@ -1494,7 +1494,7 @@ svn_auth_get_keychain_ssl_client_cert_pw
+ {
+   svn_auth__get_keychain_ssl_client_cert_pw_provider(provider, pool);
+ }
+-#endif /* DARWIN */
++#endif /* SVN_HAVE_KEYCHAIN_SERVICES */
+ 
+ #if !defined(WIN32)
+ void

default.nix

@@ -16,11 +16,19 b' let'
   pkgs = pkgs_.overridePackages (self: super: {
     # Override subversion derivation to
     #  - activate python bindings
-    subversion = super.subversion.override {
-       httpSupport = true;
-       pythonBindings = true;
-       python = self.python27Packages.python;
-    };
+    subversion = let
+      subversionWithPython = super.subversion.override {
+        httpSupport = true;
+        pythonBindings = true;
+        python = self.python27Packages.python;
+      };
+    in pkgs.lib.overrideDerivation subversionWithPython (oldAttrs: {
+      patches = oldAttrs.patches ++
+        pkgs.lib.optionals pkgs.stdenv.isDarwin [
+          # johbo: "import svn.client" fails on darwin currently.
+          ./pkgs/subversion-1.9.4-darwin.patch
+        ];
+    });
   });
 
   inherit (pkgs.lib) fix extends;