Many thanks for your quick response Werner.
This being my first foray with freetype2, I had indeed overlooked the customisation of `ftmodule.h`.
After commenting out the modules corresponding to those `.c` files that I had omitted from the compilation step, I rebuilt the product. I ended up with a library of 3.2MB, as opposed to the previous build of 2.6Mb. I then re-added it to my other, dependent Xcode project.
The first clean and build cycle of the dependent Xcode project yielded the same linker errors, so there is still something awry. I will give it another go in the morning.
Perhaps I will jettison my plan to build the freetype2 library with Xcode altogether. There are some suggestions for a command line process that I can attempt instead.