Compile code used in logging conditionally so that gcc does not complain
about unused-but-set variables.

Change-Id: I141f438694a1854d54d08cb5a74c23222dd9d85e
diff --git a/native/src/bigram_dictionary.cpp b/native/src/bigram_dictionary.cpp
index 11e6dc2..d11aee2 100644
--- a/native/src/bigram_dictionary.cpp
+++ b/native/src/bigram_dictionary.cpp
@@ -42,8 +42,10 @@
 bool BigramDictionary::addWordBigram(unsigned short *word, int length, int frequency) {
     word[length] = 0;
     if (DEBUG_DICT) {
+#ifdef FLAG_DBG
         char s[length + 1];
         for (int i = 0; i <= length; i++) s[i] = word[i];
+#endif
         LOGI("Bigram: Found word = %s, freq = %d :", s, frequency);
     }