Add (uncommited changes for 0.1.5)

setup.py

@@ -11,7 +11,7 @@ from setuptools import setup, find_packages
 setup(
 
     name="xbob.extension",
-    version="0.1.4",
+    version="0.1.5",
     description="Helps projects building Python/C++ extensions for Bob",
     license="GPLv3",
     author='Andre Anjos',

xbob/extension/__init__.py

@@ -6,8 +6,10 @@
 """A custom build class for Bob/Python extensions
 """
 
+import os
 import subprocess
 from distutils.extension import Extension as ExtensionBase
+from setuptools.command.build_ext import build_ext as build_ext_base
 
 def pkgconfig(package):
 
@@ -158,3 +160,48 @@ class Extension(ExtensionBase):
 
     # Run the constructor for the base class
     ExtensionBase.__init__(self, *args, **kwargs)
+
+class build_ext(build_ext_base):
+  '''Customized extension to build bob.python bindings in the expected way'''
+
+  linker_is_smart = None
+
+  def __init__(self, *args, **kwargs):
+    build_ext_base.__init__(self, *args, **kwargs)
+
+  def build_extension(self, ext):
+    '''Concretely builds the extension given as input'''
+
+    def linker_can_remove_symbols(linker):
+      '''Tests if the `ld` linker can remove unused symbols from linked
+      libraries. In this case, use the --no-as-needed flag during link'''
+
+      import tempfile
+      f, name = tempfile.mkstemp()
+      del f
+
+      cmd = linker + ['-Wl,--no-as-needed', '-lm', '-o', name]
+      proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+          stderr=subprocess.STDOUT)
+      output = proc.communicate()[0]
+      if os.path.exists(name): os.unlink(name)
+      return True if proc.returncode == 0 else False
+
+    def ld_ok(opt):
+      '''Tells if a certain option is a go for the linker'''
+
+      if opt.find('-L') == 0: return False
+      return True
+
+    # Some clean-up on the linker which is screwed up...
+    self.compiler.linker_so = [k for k in self.compiler.linker_so if ld_ok(k)]
+
+    if self.linker_is_smart is None:
+      self.linker_is_smart = linker_can_remove_symbols(self.compiler.linker_so)
+      if self.linker_is_smart: self.compiler.linker_so += ['-Wl,--no-as-needed']
+
+    if hasattr(self.compiler, 'dll_libraries') and \
+        self.compiler.dll_libraries is None:
+      self.compiler.dll_libraries = []
+
+    build_ext_base.build_extension(self, ext)