python: add C++ compiler support for distutils

This should help with builds against clang

pkgs/development/python-modules/numpy-distutils-C++.patch

@@ -0,0 +1,23 @@
+diff --git a/numpy/distutils/unixccompiler.py b/numpy/distutils/unixccompiler.py
+index a92ccd3..9630e91 100644
+--- a/numpy/distutils/unixccompiler.py
++++ b/numpy/distutils/unixccompiler.py
+@@ -43,10 +43,15 @@ def UnixCCompiler__compile(self, obj, src, ext, cc_args, extra_postargs, pp_opts
+         if opt not in llink_s:
+             self.linker_so = llink_s.split() + opt.split()
+ 
+-    display = '%s: %s' % (os.path.basename(self.compiler_so[0]), src)
+     try:
+-        self.spawn(self.compiler_so + cc_args + [src, '-o', obj] +
+-                   extra_postargs, display = display)
++        if self.detect_language(src) == 'c++':
++            display = '%s: %s' % (os.path.basename(self.compiler_so_cxx[0]), src)
++            self.spawn(self.compiler_so_cxx + cc_args + [src, '-o', obj] +
++                       extra_postargs, display = display)
++        else:
++            display = '%s: %s' % (os.path.basename(self.compiler_so[0]), src)
++            self.spawn(self.compiler_so + cc_args + [src, '-o', obj] +
++                       extra_postargs, display = display)
+     except DistutilsExecError:
+         msg = str(get_exception())
+         raise CompileError(msg)

pkgs/development/python-modules/numpy.nix

@@ -1,4 +1,4 @@
-{lib, python, buildPythonPackage, isPyPy, gfortran, nose, blas}:
+{lib, python, buildPythonPackage, isPy27, isPyPy, gfortran, nose, blas}:
 
 args:
 
@@ -12,6 +12,12 @@ in buildPythonPackage (args // rec {
   buildInputs = args.buildInputs or [ gfortran nose ];
   propagatedBuildInputs = args.propagatedBuildInputs or [ passthru.blas ];
 
+  patches = lib.optionals isPy27 [
+    # See cpython 2.7 patches.
+    # numpy.distutils is used by cython during it's check phase
+    ./numpy-distutils-C++.patch
+  ];
+
   preConfigure = ''
     sed -i 's/-faltivec//' numpy/distutils/system_info.py
   '';