Philippe 17/01/2022: OpenACC: Cray compiler does not like collapse directive before do concurren

src/MNH/sources_neg_correct.f90

-!MNH_LIC Copyright 2020-2021 CNRS, Meteo-France and Universite Paul Sabatier
+!MNH_LIC Copyright 2020-2022 CNRS, Meteo-France and Universite Paul Sabatier
 !MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
 !MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt
 !MNH_LIC for details. version 1.
@@ -288,7 +288,9 @@ CLOUD: select case ( hcloud )
     end do
 !   ice
     if ( krr > 3 ) then
+#ifdef MNH_COMPILER_NVHPC
 !$acc loop independent collapse(3)
+#endif
       do concurrent( ji = 1 : jiu, jj = 1 : jju, jk = 1 : jku )
         if ( prrs(ji, jj, jk, 1) < 0. .and. prrs(ji, jj, jk, 4) > 0. ) then
           zcor(ji, jj, jk)    = Min( -prrs(ji, jj, jk, 1), prrs(ji, jj, jk, 4) )