Since it is a possibility that LDFLAGS or CPPFLAGS were set with options that

in no way affect library or include directories the code must take that into
account and not assume some options were found.

diff --git a/setup.py b/setup.py
index c8d9aa0b344c5e1a2e9849d90144c52d85b74c89..0f7b0b916dc89ac486c35cb97723344553adfb36 100644 (file)
--- a/setup.py
+++ b/setup.py
@@ -270,8 +270,9 @@ class PyBuildExt(build_ext):
                 parser.error = lambda msg: None
                 parser.add_option(arg_name, dest="dirs", action="append")
                 options = parser.parse_args(env_val.split())[0]
-                for directory in options.dirs:
-                    add_dir_to_list(dir_list, directory)
+                if options.dirs:
+                    for directory in options.dirs:
+                        add_dir_to_list(dir_list, directory)
 
         if os.path.normpath(sys.prefix) != '/usr':
             add_dir_to_list(self.compiler.library_dirs,