Fix ioctl entries on 32-bit architectures with 64-bit aligned structures

Fix ioctl entries on 32-bit architectures with 64-bit aligned structures

Some ioctl constants are defined to different values on those 32-bit
architectures where structures containing a 64-bit field are aligned on
a 8-byte boundary and have a size multiple of 8 bytes, and on other
32-bit architectures.

* configure.ac: Check the size of a structure containing a 64-bit field.
* linux/32/ioctls_inc.h: Rename to ...
* linux/32/ioctls_inc_align32.h: ... this.
* linux/32/ioctls_inc_align64.h: New file.
* linux/32/ioctls_inc.h: Include either 32/ioctls_inc_align32.h
or ioctls_inc_align64.h depending on SIZEOF_STRUCT_I64_I32.
* Makefile.am (EXTRA_DIST): Add linux/32/ioctls_inc_align32.h and
* linux/32/ioctls_inc_align64.h.
* tests/ioctl.c (main): Test for VIDIOC_ENUMINPUT.
* tests/ioctl.expected: Check VIDIOC_ENUMINPUT decoding.

Reported-by: Philippe De Muyter <phdm@macqel.be>