I've just set up this environment, and it works fine (except for the Graphviz API recent modifications which I've just corrected in master):
~/Devel/libgda/libgda$ nm -g ./.libs/libgda-5.0.so.4.1.1 | grep gda_set_group
00000000000ae83d T gda_set_group_add_node
00000000000ae707 T gda_set_group_copy
00000000000ae778 T gda_set_group_free
00000000000ae97d T gda_set_group_get_n_nodes
00000000000ae8ae T gda_set_group_get_node
00000000000ae917 T gda_set_group_get_nodes
00000000000ae801 T gda_set_group_get_source
00000000000ae63c T gda_set_group_get_type
00000000000ae688 T gda_set_group_new
00000000000ae7c2 T gda_set_group_set_source
Do you have something similar?
BTW, the libgda.symbols file is used only when compiling for Windows, not for Linux where the list of symbols to export is defined by starting with "gda_"