From f2d20bab131e98e9ec1ad38f0aab774badc27d94 Mon Sep 17 00:00:00 2001
From: Ward Fisher <wfisher@ucar.edu>
Date: Mon, 11 May 2020 14:08:42 -0600
Subject: [PATCH] Added a check for compiler flag -fallow-argument-mismatch,
 introduced in gcc 10.  For the time being, this flag is required when
 compiling netCDF-Fortran with gfortran 10.  Added in support of
 https://github.com/Unidata/netcdf-fortran/issues/212

---
 configure.ac | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/configure.ac b/configure.ac
index 9e9960b9..d6fcdfab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -272,12 +272,36 @@ EOF
   fi
 fi
 
+# Test to see if fortran compiler supports the flag
+# -fallow-argument-mismatch flag introduced in gfortran 10.
+#
+# See https://github.com/Unidata/netcdf-fortran/issues/212
+ac_save_FCFLAGS="$FCFLAGS"
+AC_MSG_CHECKING([if Fortran compiler supports allow-mismatch flag])
+cat <<EOF >conftest.f90
+Program test
+USE ISO_C_BINDING, ONLY: C_PTRDIFF_T
+End Program
+EOF
+doit='$FC -c ${FCFLAGS} ${FCFLAGS_f90} -fallow-argument-mismatch conftest.f90'
+if AC_TRY_EVAL(doit); then
+   nf_allow_mismatch=yes
+   FCFLAGS="${FCFLAGS} -fallow-argument-mismatch"
+  else
+   nf_allow_mismatch=no
+fi
+AC_MSG_RESULT([$nf_allow_mismatch])
+
+
+# End testing of gfortan allow-mismatch flags.
+
 # We must have F2003 ISO bindings to build.
 if test "x$nc_iso_c_binding" = xno; then
   AC_MSG_FAILURE([Fortran 2003 interface not supported])
 fi
 nc_build_f03=yes
 
+
 # Does the user want to check into fortran type information?
 AC_MSG_CHECKING([whether fortran type sizes should be checked])
 AC_ARG_ENABLE([fortran-type-check],