S9 EXT  (sys:lstat-block-dev? string)  ==>  boolean
        (sys:lstat-char-dev? string)   ==>  boolean
        (sys:lstat-directory? string)  ==>  boolean
        (sys:lstat-pipe? string)       ==>  boolean
        (sys:lstat-regular? string)    ==>  boolean
        (sys:lstat-socket? string)     ==>  boolean
        (sys:lstat-symlink? string)    ==>  boolean
        (sys:stat-block-dev? string)   ==>  boolean
        (sys:stat-char-dev? string)    ==>  boolean
        (sys:stat-directory? string)   ==>  boolean
        (sys:stat-pipe? string)        ==>  boolean
        (sys:stat-regular? string)     ==>  boolean
        (sys:stat-socket? string)      ==>  boolean

Check if the file associated with the directory entry STRING
has a specific property and return a corresponding truth value.
Note that a return value of #F may indicate either that the given
does not exists or exists but does not have the desired property.

The SYS:STAT... procedures dereference symlimks while the
SYS:LSTAT...  procedures check the symlinks themselves. Note that
there is no SYS:STAT-SYMLINK? procedure, because it would always
deliver #F.

(sys:stat-directory? ".")   ==>  #t
(sys:stat-regular? "/dev")  ==>  #f
