Mono should ship two different pkgconfig files for Mono.Cairo 1.0 and Mono.Cairo 2.0, both specifying the complete path to the assembly. -r:something would only make gmcs look in /usr/lib/mono/2.0, mcs in 1.0
Please also see bug #64371
Mono should ship two different pkgconfig files for Mono.Cairo 1.0 and Mono.Cairo 2.0, both specifying the complete path to the assembly.
-r:something would only make gmcs look in /usr/lib/mono/2.0, mcs in 1.0
Please also see bug #64371