Here the list of the libs included into latest gnuradio (3.6.5.1) build:

libgnuradio-analog-3.6.5.1.so
libgnuradio-atsc-3.6.5.1.so
libgnuradio-audio-3.6.5.1.so
libgnuradio-blocks-3.6.5.1.so
libgnuradio-comedi-3.6.5.1.so
libgnuradio-core-3.6.5.1.so
libgnuradio-digital-3.6.5.1.so
libgnuradio-fcd-3.6.5.1.so
libgnuradio-fft-3.6.5.1.so
libgnuradio-filter-3.6.5.1.so
libgnuradio-noaa-3.6.5.1.so
libgnuradio-osmosdr-0.0.3git.so
libgnuradio-pager-3.6.5.1.so
libgnuradio-trellis-3.6.5.1.so
libgnuradio-video-sdl-3.6.5.1.so
libgnuradio-vocoder-3.6.5.1.so
libgnuradio-wavelet-3.6.5.1.so
libgruel-3.6.5.1.so
libvolk.so

Talking about POCSAG... yes you can decode it with included multimon-ng:

Here an example:
http://eliasoenal.com/2012/05/24/multimonng/
(the process seem to work also into a raspberry pi using half cpu....so why not into the N900?)

Then, multimon-ng can decode APRS AX25 AFSK DTMF CTCSS ... could you imagine?