For making things easier to maintain, I have my own set of library projects that provide shared functionality for my apps/plugins. Also, I need to encapsulate different external libraries with different APIs on Mac and Windows.
So I have some JUCE-based static libraries that include the shared stuff and also one for each platform and then I link all of them together into the final JUCE-based app or plug-in. Now the Introjucer has the habit of always including the JUCE source files into the project. In my case, however, the static libraries shouldn't containe JUCE on their own, but instead they will use the JUCE included in the app or plugin that they are being linked into.
The attached patch adds a "include JUCE" checkbox to the Introjucer Project Settings if the Project Type is "Static Library". That checkbox, which defaults to true, can then be unticked to omit the JUCE files from the static library project.