diff --git a/contrib/unaccent/unaccent.c b/contrib/unaccent/unaccent.c
old mode 100644
new mode 100755
index a337df6..4e72829
--- a/contrib/unaccent/unaccent.c
+++ b/contrib/unaccent/unaccent.c
@@ -58,7 +58,9 @@ placeChar(TrieChar *node, unsigned char *str, int lenstr, char *replaceTo, int r
 		{
 			curnode->replacelen = replacelen;
 			curnode->replaceTo = palloc(replacelen);
-			memcpy(curnode->replaceTo, replaceTo, replacelen);
+			/* palloc(0) returns a valid address, not NULL */
+			if (replaceTo) /* memcpy() is undefined for NULL pointers*/
+				memcpy(curnode->replaceTo, replaceTo, replacelen);
 		}
 	}
 	else
@@ -105,10 +107,10 @@ initTrie(char *filename)
 			while ((line = tsearch_readline(&trst)) != NULL)
 			{
 				/*
-				 * The format of each line must be "src trg" where src and trg
+				 * The format of each line must be "src [trg]" where src and trg
 				 * are sequences of one or more non-whitespace characters,
 				 * separated by whitespace.  Whitespace at start or end of
-				 * line is ignored.
+				 * line is ignored. If no trg added, a zero-length string is used.
 				 */
 				int			state;
 				char	   *ptr;
@@ -160,6 +162,13 @@ initTrie(char *filename)
 					}
 				}
 
+				/* if no trg (loop stops at state 1 or 2), use zero-length target */
+				if (state == 1 || state == 2)
+				{
+					trglen = 0;
+					state = 5;
+				}
+				
 				if (state >= 3)
 					rootTrie = placeChar(rootTrie,
 										 (unsigned char *) src, srclen,