setup.py: take potential "--build-base=<dir>" option into account

For instance, if osc is build and installed like this:
python setup.py build --build-base=<dir> ... install ...

The patch is based on Roman Neuhauser's (neuhauser@sigpipe.cz)
PR (see #229).

setup.py

@@ -25,7 +25,7 @@ def build_man_page(self):
         """
         """
         import gzip
-        man_path = os.path.join('build', 'osc.1.gz')
+        man_path = os.path.join(self.build_base, 'osc.1.gz')
         distutils.log.info('generating %s' % man_path)
         outfile = gzip.open(man_path, 'w')
         osccli = commandline.Osc(stdout=outfile)
@@ -47,10 +47,10 @@ class build_docs(distutils.command.build.Command):
     user_options = []
 
     def initialize_options(self):
-        pass
+        self.built_docs = None
 
     def finalize_options(self):
-        pass
+        self.set_undefined_options('build', ('build_base', 'built_docs'))
 
     def run(self):
         # metadata contains information supplied in setup()
@@ -61,7 +61,29 @@ def run(self):
         import sphinx
         sphinx.main(['runme', 
                     '-D', 'version=%s' % metadata.get_version(), 
-                    os.path.join('docs',), os.path.join('build', 'docs')])
+                    os.path.join('docs',), os.path.join(self.built_docs, 'docs')])
+
+
+# take a potential build-base option into account (for instance, if osc is
+# build and installed like this:
+# python setup.py build --build-base=<dir> ... install ...)
+class install_data(distutils.command.install_data.install_data, object):
+    def initialize_options(self):
+        super(install_data, self).initialize_options()
+        self.built_data = None
+
+    def finalize_options(self):
+        super(install_data, self).finalize_options()
+        self.set_undefined_options('build', ('build_base', 'built_data'))
+        data_files = []
+        for f in self.data_files:
+            # f is either a str or a (dir, files) pair
+            # (see distutils.command.install_data.install_data.run)
+            if isinstance(f, str):
+                data_files.append(os.path.join(self.built_data, f))
+            else:
+                data_files.append((f[0], [os.path.join(self.built_data, i) for i in f[1]]))
+        self.data_files = data_files
 
 
 addparams = {}
@@ -72,7 +94,7 @@ def run(self):
 
 data_files = []
 if sys.platform[:3] != 'win':
-    data_files.append((os.path.join('share', 'man', 'man1'), [os.path.join('build', 'osc.1.gz')]))
+    data_files.append((os.path.join('share', 'man', 'man1'), ['osc.1.gz']))
 
 setup(name='osc',
       version = osc.core.__version__,
@@ -93,6 +115,7 @@ def run(self):
       cmdclass = {
         'build': build_osc,
         'build_docs' : build_docs,
+        'install_data': install_data
         },
       **addparams
      )