add in m4 macro to check if cray module output flag is needed

configure.ac

@@ -254,11 +254,13 @@ if test "$enable_code_coverage" = yes; then
 fi
 AM_CONDITIONAL(COV, [test "$enable_code_coverage" = yes])
 
+
 # Require netCDF
 GX_FC_CHECK_MOD([netcdf], [], [], [AC_MSG_ERROR([Can't find the netCDF Fortran module.  Set CPPFLAGS/FCFLAGS])])
 GX_FORTRAN_SEARCH_LIBS([nf90_create], [netcdff], [use netcdf], [iret = nf90_create('foo.nc', 1, ncid)], [],
   [AC_MSG_ERROR([Can't find the netCDF Fortran library.  Set LDFLAGS/LIBS])])
 
+
 # Check if we get a floating point exception with netcdf
 # this will only get triggered if you have FPE traps enabled via FCFLAGS
 AC_MSG_CHECKING([if HDF5 version causes floating point exceptions with set flags])
@@ -273,6 +275,10 @@ if test $hdf5_fpe_bug = yes; then
 NetCDF must be built with a HDF5 version other than 1.14.3 to support floating point exception traps.])
 fi
 
+rm test.nc
+
+# Check if we need a flag to not capitalize module output (needed with cray compiler)
+GX_FC_MOD_CASE_FLAG([FCFLAGS="$FCFLAGS $FC_MOD_CASE_FLAG"])
 
 # Check if Fortran compiler has the Class, Character array assign bug
 GX_FC_CLASS_CHAR_ARRAY_BUG_CHECK()

m4/gx_fortran_options.m4

@@ -27,6 +27,7 @@
 #   GX_FC_CRAY_POINTER_FLAG([ACTION-IF-SUCCESS], [ACTION-IF-FAILURE = FAILURE])
 #   GX_FC_INTERNAL_FILE_NML()
 #   GX_FC_CHECK_MOD(module-name, [only], [action-if-found], [action-if-not-found])
+#   GX_FC_MOD_OUTPUT_CASE([ACTION-IF-SUCCESS], [ACTION-IF-FAILURE])
 #
 # DESCRIPTION
 #
@@ -405,3 +406,56 @@ AC_DEFUN([_GX_FORTRAN_PP_SRCEXT_POP], [
 AS_VAR_SET_IF([_gx_fortran_pp_srcext_save], [ac_ext=${_gx_fortran_pp_srcext_save}], [ac_ext="f"])
 unset _gx_fortran_pp_srcext_save
 ])# _GX_FORTRAN_PP_SRCEXT_POP
+
+
+# GX_FC_MOD_CASE_FLAG([ACTION-IF-SUCCESS], [ACTION-IF-FAILURE])
+# -----------------------------------------------------------------------------
+# Checks if the output .mod files are in uppercase by default.
+# This has only been seen with cray compiler. A flag is required to disable the uppercase output
+# and instead follow the case of the module name as written in the source file.
+#
+# Sets the variable FC_MOD_CASE_FLAG to hold the flag that disables the behavior.
+#
+AC_DEFUN([GX_FC_MOD_CASE_FLAG],[
+AC_LANG_PUSH([Fortran])
+AC_FC_SRCEXT(F90)
+AC_CACHE_CHECK([if Fortran flag needed for module output case], [gx_cv_fc_mod_case_flag],[
+gx_cv_fc_mod_case_flag="unknown"
+gx_mod_case_flag_FCFLAGS_save=$FCFLAGS
+
+FCFLAGS="$gx_mod_case_flag_FCFLAGS_save -c"
+AC_COMPILE_IFELSE([[module foo
+end module foo]],
+                  [],
+                  AC_MSG_ERROR(["Failed to compile test module with -c"]))
+
+# if output .mod file is capitalized, add the flag and check that it works
+if test -f "FOO.mod"; then
+  FCFLAGS="$gx_mod_case_flag_FCFLAGS_save -c -ef"
+  AC_COMPILE_IFELSE([[module foo
+                    end module mod]],
+    [])
+  if test -f "foo.mod"; then
+    gx_cv_fc_mod_case_flag="-ef"
+  fi
+else
+  gx_cv_fc_mod_case_flag="notneeded"
+fi
+
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+FCFLAGS=$gx_mod_case_flag_FCFLAGS_save
+])
+
+if test "x$gx_cv_fc_mod_case_flag" = "xunknown"; then
+  m4_default([$2],
+              [AC_MSG_ERROR([No working flag found to disable .mod filename capitalization])])
+elif test "x$gx_cv_fc_mod_case_flag" != "notneeded"; then
+  AC_DEFINE([NEEDS_MOD_OUTPUT_CASE_FLAG], 1,
+            [Define to 1 if your Fortran compiler requires a flag to match case of module names])
+  FC_MOD_CASE_FLAG=$gx_cv_fc_mod_case_flag
+  $1
+fi
+AC_LANG_POP([Fortran])
+AC_SUBST([FC_MOD_CASE_FLAG])
+])
+