What exactly is __ALIGN_STR in pnpbios/bioscalls.c for?

Hi,

include/linux/linkage.h in kernel 2.6 includes #define's for __ALIGN and __ALIGN_STR. In include/asm-i386/linkage.h, their values are changed #ifdef CONFIG_X86_ALIGNMENT_16.

It isn't obvious what exacly CONFIG_X86_ALIGNMENT_16 is for (I've heard more than one opinion), and since the __ALIGN_STR usage in drivers/pnp/pnpbios/bioscalls.c is the only non-m68k/ppc usage of one of these two #define's I wonder whether you might be able to enlighten me what CONFIG_X86_ALIGNMENT_16 exactly is for?

TIA
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed