The ornamental design for a buildingexterior, as shown and described.
FIG. 1 is a first perspective view of a building exterior embodying the new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a left side view thereof; and,
FIG. 7 is a top view thereof.
Features shown in broken lines in the Figures do not form any part of the claimed design. Broken lines immediately adjacent the solid line portions of the design form the boundary of the design, with the broken lines forming no part of the claimed design.