ccl::foreign-type-alignment returns incorrect alignment for :[un]signed-doubleword on x86

[sionescu]

Using 1.6-dev-r14265M-trunk (LinuxX8632):

(ccl::foreign-type-alignment (ccl::parse-foreign-type :signed-doubleword)) 64

The correct value is 32

[gb]

CCL::FOREIGN-TYPE-ALIGNMENT of a primitive type returns the natural alignment of that type.

Under most/all x8632 ABIs, a record field is aligned on a 32-bit boundary if its natural alignment is greater than 32 bits. (Vector types might be an exception to this; I don't remember.) CCL assumed that natural alignment was used in this case until r14222; that's now considered to be platform-specific.

? (def-foreign-type nil
    (:struct foo
       (:a :char)
       (:b :unsigned-doubleword)))
NIL
? (ccl::get-field-offset :foo.b)
4
#<FOREIGN-INTEGER-TYPE (:UNSIGNED 64) #x1413DCCE>
32

(in a post-r14222 trunk on x8632), which is consistent with what C returns here.

What's the bug, exactly ?