<linux/fs.h> conflicts with <sys/mount.h>

[andreas-schwab]

With the upcoming glibc 2.36, <linux/fs.h> conflicts with <sys/mount.h>:

In file included from /usr/include/linux/fs.h:19,
from efivarfs.c:38:
/usr/include/linux/mount.h:95:6: error: redeclaration of 'enum fsconfig_command'
95 | enum fsconfig_command {
| ^~~~~~~~~~~~~~~~
In file included from util.h:37,
from efivar.h:25,
from efivarfs.c:36:
/usr/include/sys/mount.h:189:6: note: originally defined here
189 | enum fsconfig_command
| ^~~~~~~~~~~~~~~~
/usr/include/linux/mount.h:96:9: error: redeclaration of enumerator 'FSCONFIG_SET_FLAG'
96 | FSCONFIG_SET_FLAG = 0, /* Set parameter, supplying no value /
| ^~~~~~~~~~~~~~~~~
/usr/include/sys/mount.h:191:3: note: previous definition of 'FSCONFIG_SET_FLAG' with type 'enum fsconfig_command'
191 | FSCONFIG_SET_FLAG = 0, / Set parameter, supplying no value */
| ^~~~~~~~~~~~~~~~~