`get_rootdir'
-------------

get_rootdir()
     :: Asir $B$N%k!<%H%G%#%l%/%H%jL>$r<h$j=P$9(B

RETURN
     $BJ8;zNs(B

   * UNIX $BHG$N>l9g(B, $B4D6-JQ?t(B `ASIR_LIBDIR'
     $B$,Dj5A$5$l$F$$$k>l9g$K$O$=$NCM(B, $B$5$l$F$$$J$$>l9g(B $B$K$O(B
     `/usr/local/lib/asir' $B$rJV$9(B.

   * Windows $BHG$N>l9g(B, `asirgui.exe' $B$N$"$k%G%#%l%/%H%j(B (`bin'
     $B$H$$$&L>A0$N$O$:$G$"$k(B) $B$N?F%G%#%l%/%H%j$,JV$5$l$k(B.

   *
     $B$3$N4X?t$,JV$9%G%#%l%/%H%jL>$r4p=`$H$7$?AjBP%Q%9L>$r;XDj$9$k$3$H$K$h$j(B,
     $B%$%s%9%H!<%k(B
     $B$5$l$?>l=j$K$h$i$J$$%U%!%$%kFI$_9~$_%W%m%0%i%`$r=q$/$3$H$,$G$-$k(B.

