> pkg-config --libs mono-cairo -r:/usr/lib64/pkgconfig/../../lib/mono/1.0/Mono.Cairo.dll which doesn't work, because it's in lib64, not lib. patching it to just say "-r:Mono.Cairo.dll" instead of "-r:${prefix}/lib/mono/1.0/Mono.Cairo.dll" appears to work fine, though I haven't tested extensively...
Thanks for the report - fixed in the next push