nptl: Use uintptr_t for address diagnostic in nptl/tst-pthread-getattr

Recent GCC versions warn about the attempt to return the address of a
local variable:

tst-pthread-getattr.c: In function ‘allocate_and_test’:
tst-pthread-getattr.c:54:10: error: function returns address of local variable [-Werror=return-local-addr]
   54 |   return mem;
      |          ^~~
In file included from ../include/alloca.h:3,
                 from tst-pthread-getattr.c:26:
../stdlib/alloca.h:35:23: note: declared here
   35 | # define alloca(size) __builtin_alloca (size)
      |                       ^~~~~~~~~~~~~~~~~~~~~~~
tst-pthread-getattr.c:51:9: note: in expansion of macro ‘alloca’
   51 |   mem = alloca ((size_t) (mem - target));
      |         ^~~~~~

The address itself is used in a check in the caller, so using
uintptr_t instead is reasonable.

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 6099d1468a..a5384542a8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-30  Florian Weimer  <fweimer@redhat.com>
+
+	* nptl/tst-pthread-getattr.c (allocate_and_test): Change return
+	type to uintptr_t.  Update comment.
+	(check_stack_top): Adjust.
+
 2019-07-29  Florian Weimer  <fweimer@redhat.com>
 
 	Linux: Move declaration of getdents64 to <dirent.h>.