Does ggc-page.c require MMAP_DEV_ZERO and MMAP_ANON?

[Zack Weinberg]

"H. J. Lu" <hjl@lucon.org> writes:

> checking for working mmap from /dev/zero... no
> checking for working mmap with MAP_ANON(YMOUS)... no
>
> As the result, I had
>
> /* #undef HAVE_MMAP_DEV_ZERO */
> /* #undef HAVE_MMAP_ANON */
> #define HAVE_MMAP_FILE 1
>
> in auto-host.h. Apparently, ggc-page.c doesn't work too well with
> this configuration.

This would be xvalloc mode, which is _supposed_ to work, but is rarely
if ever tested.  Can you try to debug it a bit more?

zw