diff --git a/pkgs/development/python-modules/cffi/clang.patch b/pkgs/development/python-modules/cffi/clang.patch
deleted file mode 100644
index 27674edb58b4..000000000000
--- a/pkgs/development/python-modules/cffi/clang.patch
+++ /dev/null
@@ -1,13 +0,0 @@
-diff --git a/testing/cffi1/test_recompiler.py b/testing/cffi1/test_recompiler.py
-index a3277b0..0d6e2c3 100644
---- a/testing/cffi1/test_recompiler.py
-+++ b/testing/cffi1/test_recompiler.py
-@@ -2270,7 +2270,7 @@ def test_char16_char32_type(no_cpp=False):
-         char32_t foo_4bytes(char32_t);
-     """)
-     lib = verify(ffi, "test_char16_char32_type" + no_cpp * "_nocpp", """
--    #if !defined(__cplusplus) || __cplusplus < 201103L
-+    #if !defined(__cplusplus)
-     typedef uint_least16_t char16_t;
-     typedef uint_least32_t char32_t;
-     #endif
diff --git a/pkgs/development/python-modules/cffi/default.nix b/pkgs/development/python-modules/cffi/default.nix
index 3389a6fd7054..5c99e77af56b 100644
--- a/pkgs/development/python-modules/cffi/default.nix
+++ b/pkgs/development/python-modules/cffi/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, isPy27, isPyPy, fetchPypi, libffi, pycparser, pytest }:
+{ stdenv, buildPythonPackage, isPyPy, fetchPypi, libffi, pycparser, pytest }:
 
 if isPyPy then null else buildPythonPackage rec {
   pname = "cffi";
@@ -10,15 +10,13 @@ if isPyPy then null else buildPythonPackage rec {
     sha256 = "ab87dd91c0c4073758d07334c1e5f712ce8fe48f007b86f8238773963ee700a6";
   };
 
-  patches = stdenv.lib.optional isPy27 ./clang.patch;
-
   outputs = [ "out" "dev" ];
 
   propagatedBuildInputs = [ libffi pycparser ];
   buildInputs = [ pytest ];
 
   # The tests use -Werror but with python3.6 clang detects some unreachable code.
-  NIX_CFLAGS_COMPILE = stdenv.lib.optionals stdenv.cc.isClang [ "-Wno-unused-command-line-argument" "-Wno-unreachable-code" ];
+  NIX_CFLAGS_COMPILE = stdenv.lib.optional stdenv.cc.isClang "-Wno-unreachable-code";
 
   checkPhase = ''
     py.test