Fix WALLTIME => MPI_WTIME issue when no mpi.mod

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# On branch #246-gfortran-mpich-mismatch-detection
# Changes to be committed:
#	modified:   src/tests/integration/dist_transpose/coarray_distributed_transpose.F90
#	modified:   src/tests/integration/pde_solvers/navier-stokes/coarray-shear_coll.F90
#	modified:   src/tests/performance/mpi_dist_transpose/mpi_distributed_transpose.F90
#
# Untracked files:
#	.travis-scripts/
#	build/
#

Author: zbeekman

src/tests/integration/dist_transpose/coarray_distributed_transpose.F90

@@ -41,6 +41,7 @@ module run_size
 #  else
      implicit none
      include 'mpif.h'
+#    define WALLTIME MPI_WTIME
 #  endif
 #else
   implicit none

src/tests/integration/pde_solvers/navier-stokes/coarray-shear_coll.F90

@@ -118,11 +118,7 @@ module run_size
 #  else
      implicit none
      include 'mpif.h'
-     interface WALLTIME
-       function MPI_WTIME() result(res)
-         double precision :: res
-       end function
-    end interface WALLTIME
+#    define WALLTIME MPI_WTIME
 #  endif
 #else
   implicit none

src/tests/performance/mpi_dist_transpose/mpi_distributed_transpose.F90

@@ -44,11 +44,7 @@ module mpi_run_size
 #  else
      implicit none
      include 'mpif.h'
-     interface WALLTIME
-       function MPI_WTIME() result(res)
-         double precision :: res
-       end function
-    end interface WALLTIME
+#    define WALLTIME MPI_WTIME
 #  endif
 #else
   implicit none