Execution of shell instruction in Portfile

[Nicolas Pavillon]

Hello, 

While preparing a new Portfile for kdevelop (ticket #14890, https://trac.macports.org/ticket/14890), I realized that it is required to run kbuildsycoca4 after installation to enable kdevelop to find the components it requires for running. 
Ideally, I would have wanted to run this command after activation step directly in the port, but the command needs to be run by the user (not root), and the tcl "exec" command does not enable saying with which user the command should be run. 

The best I found for now is to display a message to the user saying that he should run the command himself. Would there be another better way to make it automatic ?

Thanks in advance, 

Nicolas