Warn if deprecated cuda.nvccflags is used, smoother transition to nvcc.flags.

doc/install.txt

@@ -760,10 +760,8 @@ Then
 
      .. code-block:: cfg
 
-        [cuda]
-        nvccflags=-LC:\Python26\libs
-
         [nvcc]
+        flags=-LC:\Python26\libs
         compiler_bindir=C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\bin
 
   8) In Python do: ``import theano.sandbox.cuda``. This will compile the

theano/sandbox/cuda/nvcc_compiler.py

-import sys, os, subprocess, logging
+import sys, os, subprocess, logging, warnings
 from theano.gof.cmodule import (std_libs, std_lib_dirs, std_include_dirs, dlimport,
     get_lib_extension, local_bitwidth)
 import distutils
@@ -13,9 +13,19 @@ AddConfigVar('nvcc.compiler_bindir',
         "If defined, nvcc compiler driver will seek g++ and gcc in this directory",
         StrParam(""))
 
+AddConfigVar('cuda.nvccflags',
+        "DEPRECATED, use nvcc.flags instead",
+        StrParam("", allow_override=False),
+        in_c_key=False)
+
+if config.cuda.nvccflags != '':
+    warnings.warn('Configuration variable cuda.nvccflags is deprecated. '
+            'Please use nvcc.flags instead. You provided value: %s'
+            % config.cuda.nvccflags)
+
 AddConfigVar('nvcc.flags',
         "Extra compiler flags for nvcc",
-        StrParam(""))
+        StrParam(config.cuda.nvccflags))
 
 AddConfigVar('nvcc.fastmath',
         "",