https://bugs.gentoo.org/945707
Fix conflicting types for fabs.
--- a/C/xcBz.c
+++ b/C/xcBz.c
@@ -1397,7 +1397,6 @@ static int
 BzGetISS( int typ )
 {
   int imen[3 * BZ_MAXPOINTS], imin = 0;
-  double fabs();
   register int iss;
   register double f, point;
   register double tol = (double)(BZ_ISS - 1)/(double)BZ_ISS - (double)(BZ_ISS - 2)/(double)(BZ_ISS - 1);