Move zlib.h and friends into a subdirectory "extlibs" in lxml/include…

…s/ to separate them from lxml-version.h etc.

These files are copied by setuptools as package data from an external install directory and thus need to be in a separate package to prevent conflicting with the content of the normal lxml.includes package.

.gitignore

@@ -20,6 +20,7 @@ MANIFEST
 doc/api/lxml*.rst
 doc/api/_build/
 doc/s5/lxml-ep2008.html
+src/lxml/includes/*/
 src/lxml/includes/lxml-version.h
 src/lxml/*.html
 src/lxml/html/*.c

setup.py

@@ -180,12 +180,20 @@ def build_packages(files):
 
         header_packages = build_packages(extract_files(include_dirs))
 
+        package_filename = "__init__.py"
         for package_path, (root_path, filenames) in header_packages.items():
             if not package_path:
-                # No need to add anything to 'lxml.includes' since it has a wildcard include.
-                continue
+                # lxml.includes -> lxml.includes.extlibs
+                package_path = "extlibs"
             package = 'lxml.includes.' + package_path
             packages.append(package)
+
+            # create '__init__.py' to make sure it's considered a package
+            if package_filename not in filenames:
+                with open(os.path.join(root_path, package_filename), 'wb') as f:
+                    pass
+                filenames.append(package_filename)
+
             assert package not in package_data
             package_data[package] = filenames
             assert package not in package_dir