An alternative is to point the project that uses the shared library to the directory where netbeans places the .so it generates from the shared library project. In other words, project 1 creates a shared library, project 2 uses it. So in netbeans right click on project2, choose
properties->linker->libraries (click "...")
then click on "add library" and navigate to the folder of project 1 that is the actual netbeans project folder -- in it there will be a "dist" directory, with children, something like "/dist/Debug/linux-x86/.so" choose that .so file
note, project 1 should be created as a netbeans "C Dynamic Library" project, in which case it will automatically pre-pend "lib" in front of the project name when it generates the .so, so that the .so file's name automatically starts with "lib"..
After that, you can update and build the two projects independently, and project 2 will always see the latest build of project 1.
Sean