alloca: fix buf interaction

The stack-grows-down case is missing paren around the buf cast.

The stack-grows-up case is missing a cast with the buf assignment.
This leads to build failures due to -Werror:
vfprintf.c: In function '_IO_vfprintf_internal':
vfprintf.c:1738:16: error: initialization from incompatible pointer type [-Werror]

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 8ae6cf1f56..b8da862dc2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-24  Mike Frysinger  <vapier@gentoo.org>
+
+	* include/alloca.h [_STACK_GROWS_DOWN] (extend_alloca): Add
+	parenthesis around the buf assignment.
+	[_STACK_GROWS_UP] (extend_alloca): Add a char* cast.
+
 2015-02-24  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #16783]