Do not link libgcc and stdc++ statically

[timonegk]

Currently, libgcc and libstdc++ are linked statically. This was added in 7cc7c10 six years ago and I don't understand why it is necessary or even helpful. For me, it now breaks stuff when bio_ik is called in a python module. You can see the code here. The errors that occur with the static linking are

python: Relink `/home/timon/colcon_ws/install/bio_ik/lib/libbio_ik.so' with `/home/timon/colcon_ws/install/bio_ik/lib/libbio_ik_plugin.so' for IFUNC symbol `_Z98_ZNK6bio_ik15RobotFK_Mutator27computeApproximateMutation1EmdRKNS_14aligned_vectorINS_5FrameEEERS3_PKN6bio_ik15RobotFK_MutatorEmdRKNS_14aligned_vectorINS_5FrameEEERS5_'
python: Relink `/home/timon/colcon_ws/install/bio_ik/lib/libbio_ik.so' with `/home/timon/colcon_ws/install/bio_ik/lib/libbio_ik_plugin.so' for IFUNC symbol `_Z115_ZNK6bio_ik15RobotFK_Mutator27computeApproximateMutationsEmPKPKdRSt6vectorINS_14aligned_vectorINS_5FrameEEESaIS8_EEPKN6bio_ik15RobotFK_MutatorEmPKPKdRSt6vectorINS_14aligned_vectorINS_5FrameEEESaISA_EE'
free(): invalid pointer
[1]    758239 IOT instruction  python script.py

With this patch applied, everything works as expected without any warnings or errors.

[eholum]

This needs a rebase over the latest ros2 branch to grab the latest API changes, but it resolves the compatibility issues with fastrtps as reported in #7.

Tried and verified in https://github.com/eholum/bio_ik_test.

@sjahr Any chance of a rebase and merge?