cairo: fix unexpected cfg condition value

This crate references features that were not defined in Cargo.toml.
Add those features, even though we don't use them, so that we are
not warned to death and don't drown in the noise.

deps/cairo/Cargo.toml

@@ -22,6 +22,11 @@ pdf = []
 svg = []
 ps = []
 script = []
+win32-surface = []
+xlib = []
+xcb = []
+freetype = []
+use_glib = []
 
 [dependencies]
 libc = "0.2"