mem: Choose alignment at compile time depending on AVX enabledness.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/mem.c

@@ -57,6 +57,8 @@ void  free(void *ptr);
 
 #endif /* MALLOC_PREFIX */
 
+#define ALIGN (HAVE_AVX ? 32 : 16)
+
 /* You can redefine av_malloc and av_free in your project to use your
    memory allocator. You do not need to suppress this file because the
    linker will do it automatically. */
@@ -73,17 +75,17 @@ void *av_malloc(size_t size)
         return NULL;
 
 #if CONFIG_MEMALIGN_HACK
-    ptr = malloc(size+32);
+    ptr = malloc(size+ALIGN);
     if(!ptr)
         return ptr;
-    diff= ((-(long)ptr - 1)&31) + 1;
+    diff= ((-(long)ptr - 1)&(ALIGN-1)) + 1;
     ptr = (char*)ptr + diff;
     ((char*)ptr)[-1]= diff;
 #elif HAVE_POSIX_MEMALIGN
-    if (posix_memalign(&ptr,32,size))
+    if (posix_memalign(&ptr,ALIGN,size))
         ptr = NULL;
 #elif HAVE_MEMALIGN
-    ptr = memalign(32,size);
+    ptr = memalign(ALIGN,size);
     /* Why 64?
        Indeed, we should align it:
          on 4 for 386