When libraries are named, the developer picks some sort of version number for it. That version number goes after the .so part of the filename. My guess for that libstdc++ you have is that it is for g++ 2.7.2 (old!). You probably have another one for 2.95.2.
If you need to build a program yourself, you should have a symlink to the correct version of the shared library file. If you change what libraries are installed on the system or the path for them I think it is good to run ldconfig (packages should do this automatically). ldconfig looks for libraries and tells ld where they are. Then ld just uses it's config to find the library when it needs to. I'm not really too clear on the exact details here, but the gist of it should be correct. (If not please let me know so that I can correct my understanding!) HTH, -D :-)