Fix hang on UTF- 16 LE BOM file

Author: chrchr-github

simplecpp.cpp

@@ -282,9 +282,10 @@ class simplecpp::TokenList::Stream {
         // character is non-ASCII character then replace it with 0xff
         if (isUtf16) {
             (void)get();
-            const auto ch2 = static_cast<unsigned char>(peek());
-            unget();
-            const int ch16 = makeUtf16Char(ch, ch2);
+            const int ch2 = peek();
+            if (ch2 != EOF)
+                unget();
+            const int ch16 = makeUtf16Char(ch, static_cast<unsigned char>(ch2));
             ch = static_cast<unsigned char>(((ch16 >= 0x80) ? 0xff : ch16));
         }