make compatible with python 2.4 and check that it was not compiled while waiting for the lock

theano/sandbox/cuda/__init__.py

@@ -95,8 +95,10 @@ nvcc_compiler.add_standard_rpath(cuda_ndarray_loc)
 
 compile_cuda_ndarray = True
 
+outdated = False
 if os.path.exists(cuda_ndarray_so):
-    compile_cuda_ndarray = date >= os.stat(cuda_ndarray_so)[stat.ST_MTIME]
+    outdated = date >= os.stat(cuda_ndarray_so)[stat.ST_MTIME]
+    compile_cuda_ndarray = outdated
 if not compile_cuda_ndarray:
     try:
         # If we load a previously-compiled version, config.compiledir should
@@ -109,6 +111,19 @@ if not compile_cuda_ndarray:
 
 if compile_cuda_ndarray:
     get_lock()
+    try:
+        if not outdated:
+            # Maybe someone else compiled it while we got the lock.
+            try:
+                # If we load a previously-compiled version,
+                # config.compiledir should be in sys.path.
+                if config.compiledir not in sys.path:
+                    sys.path.append(config.compiledir)
+                from cuda_ndarray.cuda_ndarray import *
+                compile_cuda_ndarray = False
+            except ImportError:
+                compile_cuda_ndarray = True
+        if compile_cuda_ndarray:
             try:
                 if not nvcc_compiler.is_nvcc_available():
                     set_cuda_disabled()