This is exactly the kind of problem that make and relatives were invented for.

Just have a development environment with a source tree and a make script that builds a destination tree from that with appropriate information inserted. You then work in a development environment where you edit the source tree, and then build a destination tree and test there. Moving into production you update the source and build the destination. Installing for a client you create a source tree, build the destination, then delete the source.

The extra step may seem like a nuisance, but if the make process is only a simple substitution, then the build time can easily be under a second. And for that second what you get back in flexibility pays for itself again, and again, and again...