anchor.diff:  
      !  Get old component names
      kcmpnm1 = t1 % kcmpnm   ;   kcmpnm2 = t2 % kcmpnm
  +
  +   ! Turn off warnings for f90sac for zero timeshift
  +   f90sac_suppress_warnings_previous = f90sac_suppress_warnings
  +   if (f90sac_suppress_warnings /= 1) then
  +      f90sac_suppress_warnings = 1
  +   endif
   
      sum_dt = 0.
      ! Loop over the splitting parameters
  
positive.code:    ! Calculate splitting and misfit for each observation
     do i=1,n
        call CIJ_phasevels(C, 1._rs, az(i), inc(i), pol=phi2(i), vs1=vs1, vs2=vs2)
        if (present(phi_ecs)) phi_ecs(i) = phi2(i)
        dt2(i) = 1._rs/vs2 - 1._rs/vs1
        if (present(dt_ecs)) dt_ecs(i) = dt2(i)
     enddo
  
     ! If we've specified a layer thickness set dt2, otherwise normalise to
  
negative.code:    real :: dt, theta, sum_dt
     character(len=8) :: kcmpnm1, kcmpnm2
     integer :: i
     integer :: f90sac_suppress_warnings_previous
  
     ! See if we're being quiet or not: default to silet
     silent = .true.
  