Detect cython-generated files

lib/linguist/generated.rb

@@ -56,7 +56,8 @@ module Linguist
         compiled_coffeescript? ||
         xcode_project_file? ||
         generated_net_docfile? ||
-        generated_parser?
+        generated_parser? ||
+        compiled_cython_file?
     end
 
     # Internal: Is the blob an XCode project file?
@@ -158,5 +159,17 @@ module Linguist
 
       false
     end
+
+    # Internal: Is this a compiled C/C++ file from Cython?
+    #
+    # Cython-compiled C/C++ files typically contain:
+    #     /* Generated by Cython x.x.x on ... */
+    # on the first line.
+    #
+    # Return true or false
+    def compiled_cython_file?
+      return false unless ['.c', '.cpp'].include? extname
+      return lines[0].include?("Generated by Cython")
+    end
   end
 end

test/test_blob.rb

@@ -181,6 +181,10 @@ class TestBlob < Test::Unit::TestCase
 
     assert blob("JavaScript/intro.js").generated?
     assert blob("JavaScript/classes.js").generated?
+
+    # Cython-generated C/C++
+    assert blob("C/sgd_fast.c").generated?
+    assert blob("C++/wrapper_inner.cpp").generated?
   end
 
   def test_vendored