When a library is compiled in MSVC with PDB support, but later distributed without the correct PDBs, anyone attempting to link with the library will get many warnings of the form:

warning LNK4099: PDB 'XXX' was not found with 'YYY' or at 'ZZZ'; linking object as if no debug info

For various reasons Microsoft decided to make the 4099 LNK warning indelible, you cannot ignore or otherwise suppress it in any manner (there are a few other warnings in the same category). The fact that there is a list of non-ignorable warnings makes it trivial to correctly identify the list within the linker executable, so if you're stuck with 3rd party middleware with bad or missing PDBs, you can patch the linker to remove this warning.

Instructions I wrote up for some friends can be found here (they're specific to VC80, but the methodology should apply to VC7 or VC9 as well).