5.11.1 Change Project Configuration Type
As of MPLAB X IDE v2.15, when you create an Application or Library project in the New Project wizard, you are creating a project with either a configuration type application or library respectively. This means you can switch the configuration type of your existing project if you wish, with the caveats specified in the following sections.
Prebuilt and User Makefile projects are unaffected by this feature (i.e., they may not be changed to a different type of project once created).
Switch from an Application to a Library Project
When switching project configuration type from application to library, it is your responsibility to remove main(). Also, any loadables in the application project will not be built/linked once the configuration type is library. For more on loadables, see 6.3.2 Loadable Projects, Files and Symbols.
If the toolchain (i.e., XC8) does not support libraries, then the combo box will be disabled and you cannot switch the configuration to library.
Switch from a Library to an Application Project
When switching project configuration type from library to application, it is your responsibility to add main().