After removing GSM and libsamplerate they still needed for compilation
2cbbaf79 removed GSM and libsamplerate requirements.
After I removed them from the openSUSE build system as well, the compilation fails with the following:
[ 228s] CXXLD libring.la
[ 229s] /usr/lib64/gcc/x86_64-suse-linux/8/../../../../x86_64-suse-linux/bin/ld: cannot find -lgsm
[ 229s] /usr/lib64/gcc/x86_64-suse-linux/8/../../../../x86_64-suse-linux/bin/ld: cannot find -lsamplerate
[ 229s] collect2: error: ld returned 1 exit status