posted this to the list, but no answer -- no discussion! decided to repost here.
I added pd-overlay from layman, and have installed the following:
[ebuild R ] puredata-base/pd-extended-0.42.5 USE="adaptive alsa
bassemu boids bsaylor creb cxc cyclone earplug ekext ext13 flashserver
flatspace flib freeverb gem2pdp ggee hcs hid iem16 iem_adaptfilt
iem_ambi iem_bin_ambi iem_delay iem_matrix iem_roomsim iem_spec2
iem_tab iemgui iemlib iemmatrix iemxmlrpc jasch_lib loaders mapping
markex maxlib mjlib moocow moonlib motex mrpeach oscx pan pdcontainer
pddp pdogg pdp pdp_opengl pidip pmpd postlude sigpack smlib tof toxy
unauthorized vanilla vbap windowing zexy -debug -fftw -jack
-portaudio" 0 kB 
Why the article at gentoo wiki tells me to remove oscx&zexy flags from build? I didn't listened to it though.
With a few tricks, a working alsa/timidity++/puredata chain was set up
and running, to reference for other newcomers:
pdextended -alsa -alsamidi -stderr -verbose -d (config at pastebin:
The following files were installed to my system: (filelist with paths:
Now, wanted to install Androidome's script,
Multiple errors came about missing functions (like mrpeach/udpsend),
and in the UI they were outlined in red.
Also the debug log shown that search under multiple paths (none
was failed for that functions.
Looks like http://email@example.com/msg04901.html,
but checks more paths.
udpreceive 8080 ... couldn't create tried /usr/local/lib/pd-externals/sprintf.l_ia64 and failed tried /usr/lib/pd-extended/extra/sprintf.l_ia64 and failed tried /usr/local/lib/pd-externals/sprintf.pd_linux and failed tried /usr/lib/pd-extended/extra/sprintf.pd_linux and failed tried /usr/local/lib/pd-externals/sprintf/sprintf.l_ia64 and failed tried /usr/lib/pd-extended/extra/sprintf/sprintf.l_ia64 and failed tried /usr/local/lib/pd-externals/sprintf/sprintf.pd_linux and failed tried /usr/lib/pd-extended/extra/sprintf/sprintf.pd_linux and failed tried /usr/local/lib/pd-externals/sprintf.pd and failed tried /usr/lib/pd-extended/extra/sprintf.pd and failed tried /usr/local/lib/pd-externals/sprintf.pat and failed tried /usr/lib/pd-extended/extra/sprintf.pat and failed sprintf connect %s 8080 ... couldn't create tried /usr/local/lib/pd-externals/mrpeach.l_ia64 and failed tried /usr/lib/pd-extended/extra/mrpeach.l_ia64 and failed tried /usr/local/lib/pd-externals/mrpeach.pd_linux and failed tried /usr/lib/pd-extended/extra/mrpeach.pd_linux and failed tried /usr/local/lib/pd-externals/mrpeach/mrpeach.l_ia64 and failed tried /usr/lib/pd-extended/extra/mrpeach/mrpeach.l_ia64 and failed tried /usr/local/lib/pd-externals/mrpeach/mrpeach.pd_linux and failed tried /usr/lib/pd-extended/extra/mrpeach/mrpeach.pd_linux and failed error: [import]: can't load library in 'mrpeach' ... you might be able to track this down from the Find menu.
Which declare's should be added to ~/.pdextended to allow search in
/usr/lib/pdextended/extra/mrpeach and other directories?
Also it seems that
http://docs.monome.org/doku.php?id=dev:pd:simple_mlr uses an old
version of OSC (guess I name the things correctly and dont call fish an aardvark api), function names in code are like dumpOSC instead of packOSC; how to run the script at the link above with 0.42.5, can anyone tell here? (will also bug monome's list).