Fix compile warning with posix_memalign

Change-Id: I2e63c401e530525989a6aaa42115bc2d803ef821
diff --git a/src/dereko2vec.c b/src/dereko2vec.c
index aef507c..ccedb96 100644
--- a/src/dereko2vec.c
+++ b/src/dereko2vec.c
@@ -1711,7 +1711,7 @@
 void ShowCollocations() {
 	long a, b, c, d, e, window_offset, target, max_target=0, maxmax_target;
 	real f, max_f, maxmax_f;
-	real *target_sums, bestf[MAX_CC], worstbest;
+	real *target_sums=0L, bestf[MAX_CC], worstbest;
 	long besti[MAX_CC];
 	int N = 10, bestp[MAX_CC];
 	a = posix_memalign((void **) &target_sums, 128, vocab_size * sizeof(real));