I discovered this bug when I tried to emerge gnome-sharp-2.16.0: it failed because gnomevfs-sharp.dll was not found. I manually emerged gnomevfs-sharp-2.16.0 and the emergind *succeded*, but the dll was not produced and so not merged into the file system. After some investigation I discovered that my version of gnome-vfs was 2.14: I manually unmasked gnome-vfs-2.16.1, then re-emerged gnomevfs-sharp-2.16.0 and it worked (i.e., the dll was correctly built). After that I could succesfully build gnome-sharp-2.16.0.
*** This bug has been marked as a duplicate of 151710 ***