This patch fixes the following bugs:

[#413582] g++ must be called for c++ extensions
[#454030] distutils cannot link C++ code with GCC

topdir = "Lib/distutils"

* bcppcompiler.py
  (BCPPCompiler.create_static_lib): Fixed prototype, removing extra_preargs
  and extra_postargs parameters. Included target_lang parameter.
  (BCPPCompiler.link): Included target_lang parameter.

* msvccompiler.py
  (MSVCCompiler.create_static_lib): Fixed prototype, removing extra_preargs
  and extra_postargs parameters. Included target_lang parameter.
  (MSVCCompiler.link): Included target_lang parameter.

* ccompiler.py
  (CCompiler): New language_map and language_order attributes, used by
  CCompiler.detect_language().

  (CCompiler.detect_language): New method, will return the language of
  a given source, or list of sources. Individual source language is
  detected using the language_map dict. When mixed sources are used,
  language_order will stablish the language precedence.

  (CCompiler.create_static_lib, CCompiler.link, CCompiler.link_executable,
   CCompiler.link_shared_object, CCompiler.link_shared_lib):
  Inlcuded target_lang parameter.

* cygwinccompiler.py
  (CygwinCCompiler.link): Included target_lang parameter.

* emxccompiler.py
  (EMXCCompiler.link): Included target_lang parameter.

* mwerkscompiler.py
  (MWerksCompiler.link): Included target_lang parameter.

* extension.py
  (Extension.__init__): New 'language' parameter/attribute, initialized
  to None by default. If provided will overlap the automatic detection
  made by CCompiler.detect_language(), in build_ext command.

* sysconfig.py
  (customize_compiler): Check Makefile for CXX option, and also the
  environment variable CXX. Use the resulting value in the 'compiler_cxx'
  parameter of compiler.set_executables().

* unixccompiler.py
  (UnixCCompiler): Included 'compiler_cxx' in executables dict, defaulting
  to 'cc'.
  (UnixCCompiler.create_static_lib): Included target_lang parameter.
  (UnixCCompiler.link): Included target_lang parameter, and made
  linker command use compiler_cxx, if target_lang is 'c++'.

* command/build_ext.py
  (build_ext.build_extension): Pass new ext.language attribute
  to compiler.link_shared_object()'s target_lang parameter. If
  ext.language is not provided, detect language using
  compiler.detect_language(sources) instead.

* command/config.py
  (config._link): Pass already available lang parameter as target_lang
  parameter of compiler.link_executable().

Lib/distutils/unixccompiler.py

@@ -57,6 +57,7 @@ class UnixCCompiler(CCompiler):
     executables = {'preprocessor' : None,
                    'compiler'     : ["cc"],
                    'compiler_so'  : ["cc"],
+                   'compiler_cxx' : ["cc"],
                    'linker_so'    : ["cc", "-shared"],
                    'linker_exe'   : ["cc"],
                    'archiver'     : ["ar", "-cr"],
@@ -114,7 +115,7 @@ class UnixCCompiler(CCompiler):
             raise CompileError, msg
 
     def create_static_lib(self, objects, output_libname,
-                          output_dir=None, debug=0):
+                          output_dir=None, debug=0, target_lang=None):
         objects, output_dir = self._fix_object_args(objects, output_dir)
 
         output_filename = \
@@ -143,7 +144,7 @@ class UnixCCompiler(CCompiler):
              output_filename, output_dir=None, libraries=None,
              library_dirs=None, runtime_library_dirs=None,
              export_symbols=None, debug=0, extra_preargs=None,
-             extra_postargs=None, build_temp=None):
+             extra_postargs=None, build_temp=None, target_lang=None):
         objects, output_dir = self._fix_object_args(objects, output_dir)
         libraries, library_dirs, runtime_library_dirs = \
             self._fix_lib_args(libraries, library_dirs, runtime_library_dirs)
@@ -167,9 +168,12 @@ class UnixCCompiler(CCompiler):
             self.mkpath(os.path.dirname(output_filename))
             try:
                 if target_desc == CCompiler.EXECUTABLE:
-                    self.spawn(self.linker_exe + ld_args)
+                    linker = self.linker_exe[:]
                 else:
-                    self.spawn(self.linker_so + ld_args)
+                    linker = self.linker_so[:]
+                if target_lang == "c++" and self.compiler_cxx:
+                    linker[0] = self.compiler_cxx[0]
+                self.spawn(linker + ld_args)
             except DistutilsExecError, msg:
                 raise LinkError, msg
         else: