Merge branch 'susburrows/machinefiles/constance' to maint-1.0 (PR #3068)

Update machine and compiler configurations for PNNL constance machine in order to correctly identify the pnetcdf library path, fixing an issue with MPAS builds that was previously documented for ANL machines (ef09b52).

[BFB]

cime/config/e3sm/machines/config_compilers.xml

@@ -1366,7 +1366,6 @@ for mct, etc.
   <ADD_FFLAGS DEBUG="FALSE"> -O2 </ADD_FFLAGS>
   <ADD_FFLAGS DEBUG="TRUE"> -g -traceback  -O0 -fpe0 -check  all -check noarg_temp_created -ftrapuv </ADD_FFLAGS>
   <NETCDF_PATH> $(NETCDF_HOME)</NETCDF_PATH>
-  <PNETCDF_PATH>$(PNETCDFROOT)</PNETCDF_PATH>
   <CONFIG_ARGS> --host=Linux </CONFIG_ARGS>
   <PIO_FILESYSTEM_HINTS>lustre</PIO_FILESYSTEM_HINTS>
   <ADD_CPPDEFS> -DLINUX </ADD_CPPDEFS>
@@ -1378,7 +1377,6 @@ for mct, etc.
   <ADD_CFLAGS DEBUG="FALSE"> -O2 </ADD_CFLAGS>
   <ADD_FFLAGS DEBUG="FALSE"> -O2 </ADD_FFLAGS>
   <NETCDF_PATH> $(NETCDF_HOME)</NETCDF_PATH>
-  <PNETCDF_PATH>$(PNETCDFROOT)</PNETCDF_PATH>
   <CONFIG_ARGS> --host=Linux </CONFIG_ARGS>
   <PIO_FILESYSTEM_HINTS>lustre</PIO_FILESYSTEM_HINTS>
   <ADD_CPPDEFS> -DLINUX </ADD_CPPDEFS>
@@ -1390,7 +1388,6 @@ for mct, etc.
   <ADD_CFLAGS DEBUG="FALSE"> -O2 -kind=byte </ADD_CFLAGS>
   <ADD_FFLAGS DEBUG="FALSE"> -O2 -kind=byte </ADD_FFLAGS>
   <NETCDF_PATH> $(NETCDF_HOME)</NETCDF_PATH>
-  <PNETCDF_PATH>$(PNETCDFROOT)</PNETCDF_PATH>
   <CONFIG_ARGS> --host=Linux </CONFIG_ARGS>
   <PIO_FILESYSTEM_HINTS>lustre</PIO_FILESYSTEM_HINTS>
   <ADD_CPPDEFS> -DLINUX </ADD_CPPDEFS>

cime/config/e3sm/machines/config_machines.xml

@@ -1841,6 +1841,7 @@
 	     <command name="load">openmpi/1.8.3</command>
 	   </modules>
 	   <modules compiler = "intel">
+             <command name="load">pnetcdf/1.6.1</command>
 	     <command name="load">netcdf/4.3.2</command>
 	   </modules>
 	   <modules compiler = "pgi">
@@ -1860,6 +1861,9 @@
 	 <environment_variables compiler="nag">
 	   <env name="MKL_PATH">$ENV{MLIB_LIB}</env>
 	 </environment_variables>
+         <environment_variables mpilib="!mpi-serial">
+           <env name="PNETCDF_PATH">$SHELL{dirname $(dirname $(which pnetcdf_version))}</env>
+         </environment_variables>
 </machine>
 
   <machine MACH="compy">