Fix numpy.distutils to find atlas BLAS on Ubuntu

As per discussion here:
  http://mail.scipy.org/pipermail/numpy-discussion/2012-May/062363.html
numpy.distutils was failing to find BLAS on my Ubuntu 11.04 system.

The problem is that _check_libs looks for libraries in several
directories, and it turns out that the "atlas" library was found in
both /usr/lib64/atlas-base *and* in /usr/lib64, which confused
_check_libs into thinking that it couldn't be found at all.

With this fix, scipy now builds against numpy master for me.

1 files changed, 10 insertions, 3 deletions

diff --git a/numpy/distutils/system_info.py b/numpy/distutils/system_info.py
index 5ad668ef3..9c3cee3cb 100644
--- a/numpy/distutils/system_info.py
+++ b/numpy/distutils/system_info.py
@@ -665,9 +665,16 @@ class system_info:
             found_libs, found_dirs = [], []
             for dir_ in lib_dirs:
                 found_libs1 = self._lib_list(dir_, libs, exts)
-                if found_libs1:
-                    found_libs.extend(found_libs1)
-                    found_dirs.append(dir_)
+                # It's possible that we'll find the same library in multiple
+                # directories. It's also possible that we'll find some
+                # libraries on in directory, and some in another. So the
+                # obvious thing would be to use a set instead of a list, but I
+                # don't know if preserving order matters (does it?).
+                for found_lib in found_libs1:
+                    if found_lib not in found_libs:
+                        found_libs.append(found_lib)
+                        if dir_ not in found_dirs:
+                            found_dirs.append(dir_)
         else:
             found_libs = self._lib_list(lib_dirs, libs, exts)
             found_dirs = [lib_dirs]