Fix wrong alignment returned by .alignof property.

The D language expects the value to be the minimum alignment required
for the type, not the preferred alignment.

gcc/d/ChangeLog:

2018-11-17  Iain Buclaw  <ibuclaw@gdcproject.org>

	PR d/87824
	* d-target.cc (Target::alignsize): Return min_align_of_type.

From-SVN: r266234

gcc/d/ChangeLog

+2018-11-17  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	PR d/87824
+	* d-target.cc (Target::alignsize): Return min_align_of_type.
+
 2018-11-05  Iain Buclaw  <ibuclaw@gdcproject.org>
 
 	PR d/87865

gcc/d/d-target.cc

@@ -189,7 +189,7 @@ unsigned
 Target::alignsize (Type *type)
 {
   gcc_assert (type->isTypeBasic ());
-  return TYPE_ALIGN_UNIT (build_ctype (type));
+  return min_align_of_type (build_ctype (type));
 }
 
 /* Return GCC field alignment size for type TYPE.  */