Just in case, for v2.18 version:
\version "2.18.2"
%%% Clef C Ladder Style defs:
ladderStyleClef =
\markup
\override #'(filled . #t)
\path #0.001
#'((moveto 0.000 -1.500)
(lineto 0.000 -1.850)
(curveto 0.000 -1.890 0.032 -1.920 0.075 -1.920)
(curveto 0.122 -1.920 0.150 -1.890 0.150 -1.850)
(lineto 0.150 1.850)
(curveto 0.150 1.890 0.122 1.920 0.075 1.920)
(curveto 0.032 1.920 0.000 1.890 0.000 1.850)
(closepath)
(moveto 0.350 -1.500)
(lineto 0.350 -1.850)
(curveto 0.350 -1.890 0.382 -1.920 0.425 -1.920)
(curveto 0.472 -1.920 0.500 -1.890 0.500 -1.850)
(lineto 0.500 1.850)
(curveto 0.500 1.890 0.472 1.920 0.425 1.920)
(curveto 0.382 1.920 0.350 1.890 0.350 1.850)
(closepath)
(moveto 1.800 -1.500)
(lineto 1.800 -1.850)
(curveto 1.800 -1.890 1.832 -1.920 1.875 -1.920)
(curveto 1.922 -1.920 1.950 -1.890 1.950 -1.850)
(lineto 1.950 1.850)
(curveto 1.950 1.890 1.922 1.920 1.875 1.920)
(curveto 1.832 1.920 1.800 1.890 1.800 1.850)
(closepath)
(moveto 2.150 -1.500)
(lineto 2.150 -1.850)
(curveto 2.150 -1.890 2.182 -1.920 2.225 -1.920)
(curveto 2.272 -1.920 2.300 -1.890 2.300 -1.850)
(lineto 2.300 1.850)
(curveto 2.300 1.890 2.272 1.920 2.225 1.920)
(curveto 2.182 1.920 2.150 1.890 2.150 1.850)
(closepath)
(moveto 0.500 -1.100)
(curveto 0.500 -1.030 0.520 -0.970 0.620 -0.950)
(lineto 1.600 -0.670)
(curveto 1.690 -0.650 1.800 -0.620 1.800 -0.700)
(lineto 1.800 0.070)
(curveto 1.800 -0.020 1.700 -0.020 1.630 -0.050)
(lineto 0.750 -0.300)
(curveto 0.550 -0.370 0.500 -0.330 0.500 -0.200)
(closepath)
(moveto 0.500 -0.100)
(curveto 0.500 -0.030 0.520 0.030 0.620 0.050)
(lineto 1.600 0.330)
(curveto 1.690 0.350 1.800 0.380 1.800 0.300)
(lineto 1.800 1.170)
(curveto 1.800 0.980 1.700 0.980 1.630 0.950)
(lineto 0.750 0.700)
(curveto 0.550 0.630 0.500 0.670 0.500 0.800)
(closepath))
\new Staff \with {
\override Clef.stencil = #(lambda (grob) (grob-interpret-markup grob ladderStyleClef))
clefPosition = #1
middleCPosition = #1
middleCClefPosition = #1
}
{
\key aes \major
\time 3/4
c'2.
}
Cheers,