remove some GNUisms. by Dan Fandrich (dan AT coneharvesters.com)

function                                             old     new   delta
logdirs_reopen                                      1310    1308      -2
read_line_input                                     4757    4753      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-6)               Total: -6 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/gzip.c b/archival/gzip.c
index 3358469..1e56c9d 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -2078,7 +2078,7 @@
 	//if (opt & 0x4) // -v
 	argv += optind;
 
-	SET_PTR_TO_GLOBALS(xzalloc(sizeof(struct globals) + sizeof(struct globals2))
+	SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2))
 			+ sizeof(struct globals));
 	barrier();