Running "jhbuild build --check librsvg" on Ubuntu 12.10 failed because tests failed to build with the following error:
"""
make  check-TESTS
make[4]: Entering directory `/home/j-lallement/checkout/gnome/librsvg/tests'
  CC     rsvg-test.o
In file included from rsvg-test.c:43:0:
../rsvg-cairo.h:27:2: warning: #warning "Including <librsvg/rsvg-cairo.h> directly is deprecated." [-Wcpp]
rsvg-test.c: In function ‘rsvg_test_log’:
rsvg-test.c:66:5: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wmissing-format-attribute]
rsvg-test.c: In function ‘rsvg_test_html’:
rsvg-test.c:77:5: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wmissing-format-attribute]
rsvg-test.c: In function ‘rsvg_cairo_check’:
rsvg-test.c:258:5: warning: ‘rsvg_handle_set_size_callback’ is deprecated (declared at ../rsvg.h:201) [-Wdeprecated-declarations]
  CCLD   rsvg-test
/usr/bin/ld: rsvg-test.o: undefined reference to symbol 'g_object_unref'
/usr/bin/ld: note: 'g_object_unref' is defined in DSO /opt/gnome/lib64/libgobject-2.0.so.0 so try adding it to the linker command line
/opt/gnome/lib64/libgobject-2.0.so.0: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status
"""

The proposed patch attached addresses this issue