Return from int functions

Not really needed but for consistency's sake

header.c

@@ -26,6 +26,7 @@ static int write_entries(struct BIT_BUFFER *bitbuf, struct tree *parent)
 		//bb_write(bitbuf, &bit, 1);
 		bb_writebyte(bitbuf, parent->right->ch);
 	}
+	return 0;
 }
 
 int encode_header(struct BIT_BUFFER *bitbuf, struct tree *parent)
@@ -62,6 +63,7 @@ static int read_entries(struct BIT_BUFFER *bitbuf, struct tree *parent)
 	}
 
 	free(bit);
+	return 0;
 }
 
 int decode_header(struct BIT_BUFFER *bitbuf, struct tree *parent)

tree.c

@@ -108,6 +108,7 @@ static int write_entry(struct BIT_BUFFER *bitbuf, struct tree *parent, char c)
 
 		parent = left;
 	}
+	return 0;
 }
 
 int encode_tree(struct BIT_BUFFER *bitbuf, struct tree *parent, char *buf,