Added support for the 'export_symbols' parameter to 'link_shared_object()'
and 'link_shared_lib()'.  In MSVCCompiler, this is meaningful: it adds
/EXPORT: options to the linker command line.  In UnixCCompiler, it
is ignored.
diff --git a/Lib/distutils/unixccompiler.py b/Lib/distutils/unixccompiler.py
index 5e1524c..40f564a 100644
--- a/Lib/distutils/unixccompiler.py
+++ b/Lib/distutils/unixccompiler.py
@@ -178,6 +178,7 @@
                          libraries=None,
                          library_dirs=None,
                          runtime_library_dirs=None,
+                         export_symbols=None,
                          debug=0,
                          extra_preargs=None,
                          extra_postargs=None):
@@ -188,6 +189,7 @@
             libraries,
             library_dirs,
             runtime_library_dirs,
+            export_symbols,
             debug,
             extra_preargs,
             extra_postargs)
@@ -200,6 +202,7 @@
                             libraries=None,
                             library_dirs=None,
                             runtime_library_dirs=None,
+                            export_symbols=None,
                             debug=0,
                             extra_preargs=None,
                             extra_postargs=None):