+1 Good stuff (not tested, but looks fine to me, and is backwards compatible to python2.6)

It also needs

raise Error, errors

updated to

raise Error(errors)

on line 105.

Other than that, this looks good.

Looks like "as" was only introduced in Python 2.6:
http://docs.python.org/release/2.6.7/whatsnew/2.6.html#pep-3110-exception-handling-changes

because this will break pre 2.6 is it simpler to follow the note in make.py and replace the entire compatibility block with:
from shutil import ignore_patterns, copytree

which gets make.py working for me on Python 3.2. But there were a couple of other files in the document build system I had to patch too that I include below. And also 2to3 misses removing the exceptions module from the import in lib/matplotlib/sphinxext/plot_directive.py (it's after a line continuation character).

I can't verify the documents output though as my document build breaks with:
python3.2: CXX/Python3/cxx_extensions.cxx:1138: virtual Py::PythonExtensionBase::~PythonExtensionBase(): Assertion `ob_refcnt == 0' failed.

Don't think that is related and I'm still investigating, I don't have all the Python modules installed to support all the various back-ends.

--- doc/conf.py.orig
+++ doc/conf.py
@@ -174,10 +174,10 @@

 # Additional stuff for the LaTeX preamble.
 latex_preamble = """
-   \usepackage{amsmath}
-   \usepackage{amsfonts}
-   \usepackage{amssymb}
-   \usepackage{txfonts}
+   \\usepackage{amsmath}
+   \\usepackage{amsfonts}
+   \\usepackage{amssymb}
+   \\usepackage{txfonts}
 """

 # Documents to append as an appendix to all manuals.

--- doc/sphinxext/gen_rst.py.orig
+++ doc/sphinxext/gen_rst.py
@@ -37,15 +37,15 @@
                 continue

             fullpath = os.path.join(root,fname)
-            contents = file(fullpath).read()
+            contents = open(fullpath, encoding='utf8').read()
             # indent
             relpath = os.path.split(root)[-1]
             datad.setdefault(relpath, []).append((fullpath, fname, contents))

-    subdirs = datad.keys()
+    subdirs = list(datad.keys())
     subdirs.sort()

-    fhindex = file(os.path.join(exampledir, 'index.rst'), 'w')
+    fhindex = open(os.path.join(exampledir, 'index.rst'), 'w')
     fhindex.write("""\
 .. _examples-index:

@@ -77,7 +77,7 @@
             os.makedirs(outputdir)

         subdirIndexFile = os.path.join(rstdir, 'index.rst')
-        fhsubdirIndex = file(subdirIndexFile, 'w')
+        fhsubdirIndex = open(subdirIndexFile, 'w')
         fhindex.write('    %s/index.rst\n\n'%subdir)

         fhsubdirIndex.write("""\
@@ -122,14 +122,14 @@
                                   ) and
                        not noplot_regex.search(contents))
             if not do_plot:
-                fhstatic = file(outputfile, 'w')
+                fhstatic = open(outputfile, 'w')
                 fhstatic.write(contents)
                 fhstatic.close()

             if not out_of_date(fullpath, outrstfile):
                 continue

-            fh = file(outrstfile, 'w')
+            fh = open(outrstfile, 'w', encoding='utf8')
             fh.write('.. _%s-%s:\n\n'%(subdir, basename))
             title = '%s example code: %s'%(subdir, fname)
             #title = '<img src=%s> %s example code: %s'%(thumbfile, subdir, fname)

Note: We don't support pre-2.6 anymore.

It also needs
raise Error, errors
updated to
raise Error(errors)
on line 105.

On it.

Looks like "as" was only introduced in Python 2.6:
http://docs.python.org/release/2.6.7/whatsnew/2.6.html#pep-3110-exception-handling-changes

because this will break pre 2.6 is it simpler to follow the note in make.py and replace the entire compatibility block >with:
from shutil import ignore_patterns, copytree

As Ben said, python 2.5 and before are not supported.

Cheers for the patches, @cjmayo. It looks like this is ready to merge once I push @mdboom's suggestion. I think I will put the other doc fixes into another pull request so they don't hold this one up. Thanks again.

@cjmayo Those patches break doc building with python 2.7 (and possibly 2.6, too) the encoding kwarg is not a valid kwarg for the function open. I'll need to think about how best to do this.

On the import exceptions in lib/matplotlib/sphinxext/plot_directive.py. It looks like 2to3 just does not remove exceptions from the import list. There is an upstream bug that says its fixed:
http://bugs.python.org/issue2350

but I have raised a new one as it doesn't work for me in 2.7,3.2 or 3.3:
http://bugs.python.org/issue16214

@cjmayo Weird. The reproducible example you gave in that bug report (I haven't tried it) couldn't be simpler.

Looks like the codec module will work for py2/py3 file encoding compatibilities.

Ended up using io. See #1383.

These commits have been moved to #1383 to keep everything in one place.