documentation for the macro "base_filesystems"

This macro is still undocumented, please contact Isidor Zeuner <zeuner@users.sourceforge.net>.

It is defined in the file minimal.m4.

m4 code:

define(`base_filesystems',
`fs_use_xattr reiserfs system_u:system_r:kernel_t;
fs_use_trans tmpfs system_u:system_r:kernel_t;
fs_use_trans unionfs system_u:system_r:kernel_t;
genfscon sysfs / system_u:object_r:kernel_t')