Fix an issue mentioned in #366

Summary: Closes https://github.com/facebookresearch/fastText/pull/447

Differential Revision: D7111569

Pulled By: EdouardGrave

fbshipit-source-id: 61edc1960ce183901f7bb75adfccc13056e8b546

src/dictionary.cc

@@ -200,7 +200,7 @@ void Dictionary::initNgrams() {
 
 bool Dictionary::readWord(std::istream& in, std::string& word) const
 {
-  char c;
+  int c;
   std::streambuf& sb = *in.rdbuf();
   word.clear();
   while ((c = sb.sbumpc()) != EOF) {