Integer overflow in _aligned_offset_malloc

[fweimer]

In winpr/libwinpr/crt/alignment.c::_aligned_offset_malloc(), the size computation passed to malloc can overflow, causing malloc to allocate a buffer which is too small:

 82         /* minimum alignment is pointer size */
 83         if (alignment < sizeof(void*))
 84                 alignment = sizeof(void*);
 85 
 86         /* malloc size + alignment to make sure we can align afterwards */
 87         base = malloc(size + alignment + sizeof(WINPR_ALIGNED_MEM));

In the same function, the comment does not match the following check.

 74         /* alignment must be a power of 2 */
 75         if (alignment % 2 == 1)
 76                 return NULL;

[bmiklautz]

Releated PR #4961