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/ccompiler.py b/Lib/distutils/ccompiler.py
index ffad294..51f5ae0 100644
--- a/Lib/distutils/ccompiler.py
+++ b/Lib/distutils/ccompiler.py
@@ -493,6 +493,7 @@
                          libraries=None,
                          library_dirs=None,
                          runtime_library_dirs=None,
+                         export_symbols=None,
                          debug=0,
                          extra_preargs=None,
                          extra_postargs=None):
@@ -515,7 +516,13 @@
            search for libraries that were specified as bare library names
            (ie. no directory component).  These are on top of the system
            default and those supplied to 'add_library_dir()' and/or
-           'set_library_dirs()'.
+           'set_library_dirs()'.  'runtime_library_dirs' is a list of
+           directories that will be embedded into the shared library and
+           used to search for other shared libraries that *it* depends on
+           at run-time.  (This may only be relevant on Unix.)
+
+           'export_symbols' is a list of symbols that the shared library
+           will export.  (This appears to be relevant only on Windows.)
 
            'debug' is as for 'compile()' and 'create_static_lib()', with the
            slight distinction that it actually matters on most platforms
@@ -536,6 +543,7 @@
                             libraries=None,
                             library_dirs=None,
                             runtime_library_dirs=None,
+                            export_symbols=None,
                             debug=0,
                             extra_preargs=None,
                             extra_postargs=None):