Dont insert blas op with c code when config.blas.ldflags is empty.

NEWS.txt

@@ -42,6 +42,9 @@ Internal changes
  * Define new exceptions MissingInputError and UnusedInputError, and use them
    in theano.function, instead of TypeError and ValueError. (Pascal L.)
 
+Crash Fix
+ * Don't try to use blas library when told to don't use them(Frederic B.)
+
 =============
 Release Notes
 =============

theano/tensor/blas_c.py

 from theano.gof import Op
+from theano import config
+
 
 from blas import ldflags, blas_header_text
 from blas import blas_optdb, optdb, local_optimizer, EquilibriumOptimizer
@@ -239,6 +241,8 @@ class CGer(BaseBLAS, Ger):
 @local_optimizer([ger, ger_destructive])
 def use_c_ger(node):
     # Only float32 and float64 are supported for now.
+    if not config.blas.ldflags:
+        return
     if (node.op == ger and
             node.outputs[0].dtype in ['float32', 'float64']):
         return [CGer(False)(*node.inputs)]
@@ -510,6 +514,8 @@ class CGemv(BaseBLAS, Gemv):
 @local_optimizer([gemv_inplace, gemv_no_inplace])
 def use_c_gemv(node):
     # Only float32 and float64 are supported for now.
+    if not config.blas.ldflags:
+        return
     if (node.op == gemv_no_inplace and
             node.outputs[0].dtype in ['float32', 'float64']):
         return [CGemv(inplace=False)(*node.inputs)]