Fall back to ctypes if the DLFCN or dl modules are not available

src/graph_tool/dl_import.py

@@ -21,10 +21,16 @@
 import sys
 try:
     from DLFCN import RTLD_LAZY, RTLD_GLOBAL
+    dl_flags = RTLD_LAZY | RTLD_GLOBAL
 except ImportError:
     # handle strange python installations, by importing from the deprecated dl
-    # module
-    from dl import RTLD_LAZY, RTLD_GLOBAL
+    # module, otherwise from ctypes
+    try:
+        from dl import RTLD_LAZY, RTLD_GLOBAL
+        dl_flags = RTLD_LAZY | RTLD_GLOBAL
+    except ImportError:
+        from ctypes import RTLD_GLOBAL
+        dl_flags = RTLD_GLOBAL
 
 __all__ = ["dl_import"]
 
@@ -41,7 +47,7 @@ def dl_import(import_expr):
     # work properly across DSO boundaries. See http://gcc.gnu.org/faq.html#dso
 
     orig_dlopen_flags = sys.getdlopenflags()
-    sys.setdlopenflags(RTLD_LAZY | RTLD_GLOBAL)
+    sys.setdlopenflags(dl_flags)
 
     exec import_expr in local_dict, global_dict
 

src/graph_tool/run_action/inline.py

@@ -21,7 +21,7 @@ import sys, string, hashlib, os.path, re, glob
 from .. import *
 from .. import libgraph_tool_core
 import numpy
-from .. dl_import import RTLD_LAZY, RTLD_GLOBAL
+from .. dl_import import dl_flags
 
 try:
     import scipy.weave
@@ -251,7 +251,7 @@ def inline(code, arg_names=None, local_dict=None,
     # friends to work properly across DSO boundaries. See
     # http://gcc.gnu.org/faq.html#dso
     orig_dlopen_flags = sys.getdlopenflags()
-    sys.setdlopenflags(RTLD_LAZY | RTLD_GLOBAL)
+    sys.setdlopenflags(dl_flags)
 
     # call weave and pass all the updated kw arguments
     ret_vals = \