xsnow not building

[Noah]

FreeBSD 4.8-stable

still getting used to installing X applications here:

xsnow is not building from /usr/ports


# make install clean                       [/usr/ports/x11/xsnow]
===>  Vulnerability check disabled
>> xsnow-1.42.tar.gz doesn't seem to exist in /usr/ports/distfiles/.
>> Attempting to fetch from http://www.euronet.nl/~rja/Xsnow/.
Receiving xsnow-1.42.tar.gz (56752 bytes): 100%
56752 bytes transferred in 19.6 seconds (2.83 kBps)
===>  Extracting for xsnow-1.42
>> Checksum OK for xsnow-1.42.tar.gz.
===>  Patching for xsnow-1.42
===>   xsnow-1.42 depends on file: /usr/X11R6/lib/X11/config/date.def - found
===>   xsnow-1.42 depends on shared library: X11.6 - found
===>  Configuring for xsnow-1.42
env: xmkmf: No such file or directory
*** Error code 127


--- snip ---

% pkg_info | grep XFree86                                       [~]
XFree86-3.3.6_11    X11R6.3/XFree86 core distribution
XFree86-font100dpi-4.2.0 XFree86-4 bitmap 100 dpi fonts
XFree86-font75dpi-4.2.0 XFree86-4 bitmap 75 dpi fonts
XFree86-fontCyrillic-4.2.0 XFree86-4 Cyrillic Fonts
XFree86-fontDefaultBitmaps-4.2.0 XFree86-4 default bitmap fonts
XFree86-fontEncodings-4.2.0 XFree86-4 font encoding files
XFree86-fontScalable-4.2.0 XFree86-4 Scalable font files
imake-4.2.0_1       Imake and other utilities from XFree86
imake-4.3.0         Imake and other utilities from XFree86

--- snip ---

any clues here?