i386: Increase MALLOC_ALIGNMENT to 16 [BZ #21120]

GCC 7 changed the definition of max_align_t on i386:

https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=9b5c49ef97e63cc63f1ffa13baf771368105ebe2

As a result, glibc malloc no longer returns memory blocks which are as
aligned as max_align_t requires.

This causes malloc/tst-malloc-thread-fail to fail with an error like this
one:

error: allocation function 0, size 144 not aligned to 16

This patch moves the MALLOC_ALIGNMENT definition to <malloc-alignment.h>
and increases the malloc alignment to 16 for i386.

	[BZ #21120]
	* malloc/malloc-internal.h (MALLOC_ALIGNMENT): Moved to ...
	* sysdeps/generic/malloc-alignment.h: Here.  New file.
	* sysdeps/i386/malloc-alignment.h: Likewise.
	* sysdeps/generic/malloc-machine.h: Include <malloc-alignment.h>.

1 files changed, 0 insertions, 10 deletions

diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h
index dbd801a58e..6a62717e69 100644
--- a/malloc/malloc-internal.h
+++ b/malloc/malloc-internal.h
@@ -58,16 +58,6 @@
 /* The corresponding word size.  */
 #define SIZE_SZ (sizeof (INTERNAL_SIZE_T))
 
-/* MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks.  It
-   must be a power of two at least 2 * SIZE_SZ, even on machines for
-   which smaller alignments would suffice. It may be defined as larger
-   than this though. Note however that code and data structures are
-   optimized for the case of 8-byte alignment.  */
-#ifndef MALLOC_ALIGNMENT
-# define MALLOC_ALIGNMENT (2 * SIZE_SZ < __alignof__ (long double) \
-                           ? __alignof__ (long double) : 2 * SIZE_SZ)
-#endif
-
 /* The corresponding bit mask value.  */
 #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)