Thanks a lot for your time, Kjell...
After this, I decided to rebuild all my Linux system... and the problems about 'pangocairo' disapeared; but no at all in building the last g*mm releases, because the process broke at 'gtk+' step, as shown below,
[...]
checking Pango flags... -pthread -I/opt/gnome/include/pango-1.0 -I/opt/gnome/include/glib-2.0 -I/opt/gnome/lib/glib-2.0/include -I/usr/include/freetype2 -I/opt/gnome/include/harfbuzz -I/usr/local/include/pango-1.0 -I/usr/local/include/cairo -I/usr/local/include/pixman-1 -I/usr/local/include/freetype2 -I/usr/include/libpng12 -L/opt/gnome/lib -L/usr/local/lib -lpangocairo-1.0 -lpango-1.0 -lcairo -lgobject-2.0 -lglib-2.0
checking for cairo_surface_set_device_scale... no
checking for GDK_DEP... yes
checking for ATK... no
configure: error: Package requirements (atk atk-bridge-2.0) were not met:
No package 'atk-bridge-2.0' found
[...]
This seems strange too, because 'ATk' and 'ATkmm' packages are already builded (& installed).