add check in case compiler doesn't support inexact halting

Author: peterdschwartz

components/elm/src/biogeophys/SoilStateType.F90

@@ -469,8 +469,10 @@ subroutine InitCold(this, bounds)
     ! Try to read soil information from the file.
     call ncd_io(ncid=ncid, varname='ZSOI', flag='read', data=zsoifl, dim1name=grlnd, readvar=readvar)
     if (.not. readvar ) then
-       call ieee_set_flag(ieee_all,.false.)
-       call ieee_set_halting_mode(ieee_inexact, .false.)
+       if (ieee_support_halting(ieee_inexact)) then
+          call ieee_set_flag(ieee_all,.false.)
+          call ieee_set_halting_mode(ieee_inexact, .false.)
+       end if 
        do j = 1, nlevsoifl
           zsoifl(j) = scalez*(exp(zecoeff*(dble(j)-0.5_r8))-1._r8)    !node depths
        enddo

components/elm/src/main/initVerticalMod.F90

@@ -171,8 +171,10 @@ subroutine initVertical(bounds, snow_depth, thick_wall, thick_roof)
        !    Soil layers not available from the input, and no additional layers needed. Use the
        ! default soil thickness settings.
        ! -----------------------------------------------------------------
-       call ieee_set_flag(ieee_all,.false.)
-       call ieee_set_halting_mode(ieee_inexact, .false.)
+       if (ieee_support_halting(ieee_inexact)) then
+          call ieee_set_flag(ieee_all,.false.)
+          call ieee_set_halting_mode(ieee_inexact, .false.)
+       end if 
 
        do j = 1, nlevgrnd
           zsoi(j) = scalez*(exp(zecoeff*(dble(j)-0.5_r8))-1._r8)    !node depths