Our 1.125s delay does not seem to be long enough to be reliable with the Borland "make" tool. Use a longer delay for Borland.
Classify .manifest sources separately, add dependencies on them, and pass them to the MS manifest tool to merge with linker-generated manifest files. Inspired-by: Gilles Khouzam <gillesk@microsoft.com>
This will allow more granular checks than the main BuildDepends test. Start with a simple single-source C program.