Revert "Fix #2183 porterstemmer causes make json to fail"

This is a breaking change. So we move the change into master branch.
This reverts commit f1518c5fc4.

CHANGES

@@ -21,7 +21,6 @@ Bugs fixed
 * #2071: Fix same footnote in more than two section titles => LaTeX/PDF Bug
 * #2040: Fix UnicodeDecodeError in sphinx-apidoc when author contains non-ascii characters
 * #2193: Fix shutil.SameFileError if source directory and destination directory are same
-* #2183: Fix porterstemmer causes `make json` to fail
 
 
 Release 1.3.3 (released Dec 2, 2015)

sphinx/search/en.py

@@ -11,6 +11,13 @@
 
 from sphinx.search import SearchLanguage
 
+try:
+    # http://bitbucket.org/methane/porterstemmer/
+    from porterstemmer import Stemmer as CStemmer
+    CSTEMMER = True
+    PYSTEMMER = False
+except ImportError:
+    CSTEMMER = False
     try:
         from Stemmer import Stemmer as PyStemmer
         PYSTEMMER = True
@@ -224,7 +231,11 @@ class SearchEnglish(SearchLanguage):
     stopwords = english_stopwords
 
     def init(self, options):
-        if PYSTEMMER:
+        if CSTEMMER:
+            class Stemmer(CStemmer):
+                def stem(self, word):
+                    return self(word.lower())
+        elif PYSTEMMER:
             class Stemmer(object):
                 def __init__(self):
                     self.stemmer = PyStemmer('porter')