auth: precompute authnameslen
auth: precompute authnameslen

Signed-off-by: Julien Danjou <5c682c2d1ec4073e277f9ba9f4bdf07e5794dabe@danjou.info>

stapelberg/libxcb,topcat/xcb-win32,topcat/xcb-win32,topcat/xcb-win32,topcat/xcb-win32,stapelberg/libxcb,topcat/xcb-win32,stapelberg/libxcb