NOTE: to compile the C daemon you must have a working AOSP source tree, and copy it to external folder.
Do something like:

$AOSP_SRC=/path/to/aosp
$VNC_DAEMON=/path_to_vnc/droidvncdaemon

cp -fr $VNC_DAEMON/droidvncdaemon $AOSP_SRC
cd $AOSP_SRC
. build/envsetup.sh
# lunch
mmm external/droidvncdaemon

Thats it. You will have androidvncserver_froyo (for 2.2 down) and androidvncserver_ginger (for 2.3+) in $AOSP_SRC/out/target/product/generic/system/bin/

I think this process is quite difficult, anyone knows how to build external packages outside AOSP tree?