found this..
http://www.fsf.org/licensing/licenses/gpl-faq.html#GPLPluginsInNF
Can I apply the GPL when writing a plug-in for a non-free program?
If the program uses fork and exec to invoke plug-ins, then the plug-ins are separate programs, so the license for the main program makes no requirements for them. So you can use the GPL for a plug-in, and there are no special requirements.
If the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug-ins. This means that combination of the GPL-covered plug-in with the non-free main program would violate the GPL. However, you can resolve that legal problem by adding an exception to your plug-in's license, giving permission to link it with the non-free main program
so all i have to do is declare permission for use in non-free programs. is that correct?
http://www.fsf.org/licensing/licenses/gpl-faq.html#GPLPluginsInNF
Can I apply the GPL when writing a plug-in for a non-free program?
If the program uses fork and exec to invoke plug-ins, then the plug-ins are separate programs, so the license for the main program makes no requirements for them. So you can use the GPL for a plug-in, and there are no special requirements.
If the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug-ins. This means that combination of the GPL-covered plug-in with the non-free main program would violate the GPL. However, you can resolve that legal problem by adding an exception to your plug-in's license, giving permission to link it with the non-free main program
so all i have to do is declare permission for use in non-free programs. is that correct?