[OE-core] site/x32-linux: Specify double alignment

[Richard Purdie]

Double alignment is 8 bytes on x32 but it is defaulting to 4 currently.
This leads to various issues and fontconfig fails to build due to the
mismatch triggering assert failures.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>

diff --git a/meta/site/x32-linux b/meta/site/x32-linux
index 7ce6551..36ee68b 100644
--- a/meta/site/x32-linux
+++ b/meta/site/x32-linux
@@ -4,6 +4,7 @@ ac_cv_sizeof_off_t=${ac_cv_sizeof_off_t=8}
 ac_cv_sizeof_ino_t=${ac_cv_sizeof_ino_t=8}
 ac_cv_sizeof_dev_t=${ac_cv_sizeof_dev_t=8}
 ac_cv_sys_file_offset_bits=${ac_cv_sys_file_offset_bits=64}
+ac_cv_alignof_double=8
 
 # glib
 glib_cv_sizeof_gmutex=${glib_cv_sizeof_gmutex=32}