[at-spi2-core] configure: use AC_CHECK_ALIGNOF() instead of custom DBIND_CHECK_ALIGNOF()

[Mike Gorse <mgorse src gnome org>]

commit f239b92014fc667bf660b17d6e4458c6cbfbf9b4
Author: Thomas Petazzoni <thomas petazzoni free-electrons com>
Date:   Wed Jun 25 19:45:28 2014 +0200

    configure: use AC_CHECK_ALIGNOF() instead of custom DBIND_CHECK_ALIGNOF()
    
    DBIND_CHECK_ALIGNOF() is a custom autoconf macro from at-spi2-core
    that tests the alignment required on the current platform for a given
    C type. Unfortunately, this macro uses AC_TRY_RUN(), which requires
    running a test program on the target platform, which is fundamentally
    incompatible with cross-compilation.
    
    Therefore, this patch switches the configure.ac code to use
    AC_CHECK_ALIGNOF() instead, which is available in the standard set of
    autoconf macros, and is able to test the required alignment for C
    types without using AC_TRY_RUN(). Consequently, it adjusts the
    dbind/dbind-config.h.in definitions to use the definitions created by
    the AC_CHECK_ALIGNOF() macros, which are not substituted by autoconf,
    but directly available from config.h.
    
    Signed-off-by: Thomas Petazzoni <thomas petazzoni free-electrons com>

 configure.ac            |   18 ++++++++++--------
 dbind/dbind-config.h.in |   16 ++++++++--------
 2 files changed, 18 insertions(+), 16 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 31733bd..cb8e89a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -192,14 +192,16 @@ AC_SUBST(LIBTOOL_EXPORT_OPTIONS)
 dnl find sizes & alignments
 orig_CPPFLAGS=$CPPFLAGS
 CPPFLAGS="$CPPFLAGS $DBUS_CFLAGS"
-DBIND_CHECK_ALIGNOF(char)
-DBIND_CHECK_ALIGNOF(dbus_bool_t)
-DBIND_CHECK_ALIGNOF(dbus_int16_t)
-DBIND_CHECK_ALIGNOF(dbus_int32_t)
-DBIND_CHECK_ALIGNOF(dbus_int64_t)
-DBIND_CHECK_ALIGNOF(double)
-DBIND_CHECK_ALIGNOF(dbind_pointer)
-DBIND_CHECK_ALIGNOF(dbind_struct)
+AC_CHECK_ALIGNOF(char)
+AC_CHECK_ALIGNOF(dbus_bool_t, [#include <dbus/dbus.h>])
+AC_CHECK_ALIGNOF(dbus_int16_t, [#include <dbus/dbus.h>])
+AC_CHECK_ALIGNOF(dbus_int32_t, [#include <dbus/dbus.h>])
+AC_CHECK_ALIGNOF(dbus_int64_t, [#include <dbus/dbus.h>])
+AC_CHECK_ALIGNOF(double, [#include <dbus/dbus.h>])
+AC_CHECK_ALIGNOF(dbind_pointer, [AC_INCLUDES_DEFAULT
+typedef void *dbind_pointer;])
+AC_CHECK_ALIGNOF(dbind_struct, [AC_INCLUDES_DEFAULT
+typedef struct {char s1;} dbind_struct;])
 
 GTK_DOC_CHECK([1.09])
 
diff --git a/dbind/dbind-config.h.in b/dbind/dbind-config.h.in
index 3da421e..779c4c6 100644
--- a/dbind/dbind-config.h.in
+++ b/dbind/dbind-config.h.in
@@ -1,8 +1,8 @@
-#define DBIND_ALIGNOF_CHAR          @DBIND_ALIGNOF_CHAR@
-#define DBIND_ALIGNOF_DBIND_POINTER @DBIND_ALIGNOF_DBIND_POINTER@
-#define DBIND_ALIGNOF_DBIND_STRUCT  @DBIND_ALIGNOF_DBIND_STRUCT@
-#define DBIND_ALIGNOF_DBUS_BOOL_T   @DBIND_ALIGNOF_DBUS_BOOL_T@
-#define DBIND_ALIGNOF_DBUS_INT16_T  @DBIND_ALIGNOF_DBUS_INT16_T@
-#define DBIND_ALIGNOF_DBUS_INT32_T  @DBIND_ALIGNOF_DBUS_INT32_T@
-#define DBIND_ALIGNOF_DBUS_INT64_T  @DBIND_ALIGNOF_DBUS_INT64_T@
-#define DBIND_ALIGNOF_DOUBLE        @DBIND_ALIGNOF_DOUBLE@
+#define DBIND_ALIGNOF_CHAR          ALIGNOF_CHAR
+#define DBIND_ALIGNOF_DBIND_POINTER ALIGNOF_DBIND_POINTER
+#define DBIND_ALIGNOF_DBIND_STRUCT  ALIGNOF_DBIND_STRUCT
+#define DBIND_ALIGNOF_DBUS_BOOL_T   ALIGNOF_DBUS_BOOL_T
+#define DBIND_ALIGNOF_DBUS_INT16_T  ALIGNOF_DBUS_INT16_T
+#define DBIND_ALIGNOF_DBUS_INT32_T  ALIGNOF_DBUS_INT32_T
+#define DBIND_ALIGNOF_DBUS_INT64_T  ALIGNOF_DBUS_INT64_T
+#define DBIND_ALIGNOF_DOUBLE        ALIGNOF_DOUBLE