*: more uniform naming: s/xmalloc_getline/xmalloc_fgetline/

diff --git a/archival/tar.c b/archival/tar.c
index 7bd7955..0c90ac0 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -660,7 +660,7 @@
 		tmp = cur;
 		cur = cur->link;
 		free(tmp);
-		while ((line = xmalloc_getline(src_stream)) != NULL) {
+		while ((line = xmalloc_fgetline(src_stream)) != NULL) {
 			/* kill trailing '/' unless the string is just "/" */
 			char *cp = last_char_is(line, '/');
 			if (cp > line)