mi: Correct a miscall of abs() to instead call fabs()

miarc.c:1714:9: warning: using integer absolute value function
'abs' when
      argument is of floating point type [-Wabsolute-value,Semantic Issue]
    if (abs(parc->angle2) >= 360.0)
        ^
miarc.c:1714:9: note: use function 'fabs' instead [Semantic Issue]
    if (abs(parc->angle2) >= 360.0)
        ^~~
        fabs

Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>

mi/miarc.c

@@ -1711,7 +1711,7 @@ miGetArcPts(SppArcPtr parc,     /* points to an arc */
         y1 = y2;
     }
     /* adjust the last point */
-    if (abs(parc->angle2) >= 360.0)
+    if (fabs(parc->angle2) >= 360.0)
         poly[cpt + i - 1] = poly[0];
     else {
         poly[cpt + i - 1].x = (miDcos(st + et) * parc->width / 2.0 + xc);