fortran: add mismatch flags to mpif77 wrapper

Remove the AC_MSG_ERROR on needing the Fortran mismatch flag and add the
flag to the mpif77 wrapper.

This will not affect users of modern Fortran MPI applications who are
likely to use `mpifort` or `mpif90` and uses the mpi module interface.

Users who use `mpif77` is likely to use `mpif.h` interface and will
require the ignore-mismatch compiler flags to compile their MPI
applications.

By adding the extra flags to mpif77 wrapper only, we hope to strike a
balance of convenience and impact.

configure.ac

@@ -1970,15 +1970,12 @@ if test "$enable_f77" = "yes" ; then
     # of different types (e.g., for MPI_Send)
     PAC_PROG_F77_MISMATCHED_ARGS(addarg,yes)
     if test "X$addarg" != "X" ; then
-        # We could add the names of all of the MPI routines that
-        # accept different types.  Instead, we fail cleanly.
-        # Some Fortran compilers allow you to turn off checking for
-        # mismatched arguments for *all* routines.  Adding an argument
-	# that turns off checking for *everything* is not something that
-	# configure should do - if the user wants this, they can follow
-	# the instructions in the following error message.
-        AC_MSG_ERROR([The Fortran compiler $FC does not accept programs that call the same routine with arguments of different types without the option $addarg.  Rerun configure with FCFLAGS=$addarg])
+        # Code using mpif.h interface will likely need this flag to compile.
+        # Code with `use mpi` or `use mpi_f08` do not need this flag.
+        # Add the flag to mpif77 wrappers.
+        WRAPPER_EXTRA_F77_FLAGS="$addarg"
     fi
+    AC_SUBST(WRAPPER_EXTRA_F77_FLAGS)
 
     bindings="$bindings f77"
     AC_DEFINE(HAVE_FORTRAN_BINDING,1,[Define if Fortran is supported])

src/env/mpifort.bash.in

@@ -343,6 +343,11 @@ if test "@INTERLIB_DEPS@" = "no" -o "${interlib_deps}" = "no" ; then
     final_libs="${final_libs} @LIBS@ @WRAPPER_LIBS@"
 fi
 
+extra_f77_flags="@WRAPPER_EXTRA_F77_FLAGS@"
+if test "mpif77" = ${0##*/} -a -n "$extra_f77_flags" ; then
+    final_fcflags="${final_fcflags} $extra_f77_flags"
+fi
+
 # A temporary statement to invoke the compiler
 # Place the -L before any args in case there are any mpi libraries in there.
 # Eventually, we'll want to move this after any non-MPI implementation

src/env/mpifort.sh.in

@@ -360,6 +360,11 @@ if test "@INTERLIB_DEPS@" = "no" -o "${interlib_deps}" = "no" ; then
     final_libs="${final_libs} @LIBS@ @WRAPPER_LIBS@"
 fi
 
+extra_f77_flags="@WRAPPER_EXTRA_F77_FLAGS@"
+if test "mpif77" = ${0##*/} -a -n "$extra_f77_flags" ; then
+    final_fcflags="${final_fcflags} $extra_f77_flags"
+fi
+
 # A temporary statement to invoke the compiler
 # Place the -L before any args in case there are any mpi libraries in there.
 # Eventually, we'll want to move this after any non-MPI implementation

test/mpi/configure.ac

@@ -1034,26 +1034,6 @@ EOF
     AC_LANG_FORTRAN77
     PAC_PROG_F77_NAME_MANGLE
 
-    # Check that the Fortran compiler will allow us to pass arguments
-    # of different types (e.g., for MPI_Send)
-    # Any strict Fortran compiler will require that the arguments be
-    # the same type - currently, the NAG Fortran compiler (nagfor) is known
-    # to enforce this.
-    # We could set the FFLAGS/FCFLAGS values with the option that disables
-    # this check (if we found one), but because that may affect other tests,
-    # instead we tell the user and exit.
-    PAC_PROG_F77_MISMATCHED_ARGS(addarg,yes)
-    if test "X$addarg" != "X" ; then
-        # We could add the names of all of the MPI routines that
-        # accept different types.  Instead, we fail cleanly.
-        # Some Fortran compilers allow you to turn off checking for
-        # mismatched arguments for *all* routines.  Adding an argument
-        # that turns off checking for *everything* is not something that
-        # configure should do - if the user wants this, they can follow
-        # the instructions in the following error message.
-        AC_MSG_ERROR([The Fortran compiler $F77 does not accept programs that call the same routine with arguments of different types without the option $addarg.  Rerun configure with FFLAGS=$addarg])
-    fi
-
     # Check whether we need -lU77 to get iargc and getarg, which
     # are used for a few of the tests in spawn (U77 was needed with
     # the native compilers on HPUX.  See the aclocal_f77(old).m4 file,