Found the following significant warnings:
  paircount.cpp:68:18: warning: using integer absolute value function 'abs' when argument is of floating point type [-Wabsolute-value]
  paircount.cpp:94:18: warning: using integer absolute value function 'abs' when argument is of floating point type [-Wabsolute-value]
See '/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/physx.Rcheck/00install.out' for details.