Simplify by removing HAVE_STRUCT_ATTRIBUTE_ALIGNED

* configure.ac (HAVE_STRUCT_ATTRIBUTE_ALIGNED): Remove.  No longer
needed, since we no longer rely on __attribute__ ((aligned (8))).
All uses removed.
* src/emacs-module.c (HAVE_STRUCT_ATTRIBUTE_ALIGNED): Remove.
(lisp_to_value): Simplify now that we no longer need to worry
whether HAVE_STRUCT_ATTRIBUTE_ALIGNED is false.

admin/CPP-DEFINES

@@ -103,7 +103,6 @@ HAVE_ALARM
 HAVE_ALLOCA
 HAVE_ALLOCA_H
 HAVE_ALSA
-HAVE_ATTRIBUTE_ALIGNED
 HAVE_BDFFONT
 HAVE_BOXES
 HAVE_C99_STRTOLD

configure.ac

@@ -5113,22 +5113,6 @@ else
 fi
 AC_SUBST(LIBXMENU)
 
-AC_CACHE_CHECK([for struct alignment],
-  [emacs_cv_struct_alignment],
-  [AC_COMPILE_IFELSE(
-     [AC_LANG_PROGRAM([[#include <stddef.h>
-			struct __attribute__ ((aligned (8))) s { char c; };
-			struct t { char c; struct s s; };
-			char verify[offsetof (struct t, s) == 8 ? 1 : -1];
-		      ]])],
-     [emacs_cv_struct_alignment=yes],
-     [emacs_cv_struct_alignment=no])])
-if test "$emacs_cv_struct_alignment" = yes; then
-  AC_DEFINE([HAVE_STRUCT_ATTRIBUTE_ALIGNED], 1,
-    [Define to 1 if 'struct __attribute__ ((aligned (N)))' aligns the
-     structure to an N-byte boundary.])
-fi
-
 if test "${GNU_MALLOC}" = "yes" ; then
   AC_DEFINE(GNU_MALLOC, 1,
 	    [Define to 1 if you want to use the GNU memory allocator.])

src/emacs-module.c

@@ -998,10 +998,6 @@ lisp_to_value_bits (Lisp_Object o)
   return (emacs_value) p;
 }
 
-#ifndef HAVE_STRUCT_ATTRIBUTE_ALIGNED
-enum { HAVE_STRUCT_ATTRIBUTE_ALIGNED = 0 };
-#endif
-
 /* Convert O to an emacs_value.  Allocate storage if needed; this can
    signal if memory is exhausted.  Must be an injective function.  */
 static emacs_value
@@ -1029,19 +1025,6 @@ lisp_to_value (emacs_env *env, Lisp_Object o)
       /* Package the incompressible object pointer inside a pair
 	 that is compressible.  */
       Lisp_Object pair = Fcons (o, ltv_mark);
-
-      if (! HAVE_STRUCT_ATTRIBUTE_ALIGNED)
-	{
-	  /* Keep calling Fcons until it returns a compressible pair.
-	     This shouldn't take long.  */
-	  while ((intptr_t) XCONS (pair) & (GCALIGNMENT - 1))
-	    pair = Fcons (o, pair);
-
-	  /* Plant the mark.  The garbage collector will eventually
-	     reclaim any just-allocated incompressible pairs.  */
-	  XSETCDR (pair, ltv_mark);
-	}
-
       v = (emacs_value) ((intptr_t) XCONS (pair) + Lisp_Cons);
     }