I have tcdl tags written out in my jsp pages (publication target is set to REL, and it is not an option to change it to jsp).
What do I need to include in my jsp pages to make these tags resolve?
Tnx.
Publication target language "REL" means that the deployer is expected not to convert the tcdl tags to JSP custom taglib directives; also see the SDL tridion 2013 online documentation.
Instead these get executed by the PageContentAssembler and the ComponentPresentationAssembler at request time; if you are publishing flat JSP pages from Tridion to your webapp container your pages should not write out any tcdl tags as there is nothing to "interpret" the tags at request time!
If these tags are inside dynamic component presentations make sure you are using the ComponentPresentationAssembler to output DCP content into the page instead of the ComponentPresentationFactory.
Edit: So in essence you want your DCPs in the database to contain tcdl tags but static pages on your filesystem to contain JSP taglib references? You could set the target language to "none" and configure the deployer to handle the tcdl tags for pages differently than for component presentations but i'm not entire sure this is a viable approach and I don't currently have access to a system to verify this (but hopefully someone else can validate this suggestion?)
Alternatively you could create a TBB to convert tcdl tags to JSP taglib references and add this to your page templates (this would not impact your component presentation output as DCP output does not pass through your page template); this way you can leave the target language as "REL" although technically you would be duplicating out-of-box functionality of Tridion...