Get cime_developer building again on skybridge.

For reasons that are unclear to me, skybridge completely stopped
working a few days ago. With MPI_PATH not defined, I'm not sure
how it ever worked.

cime_config/acme/machines/config_compilers.xml

@@ -640,16 +640,12 @@ for mct, etc.
   <ADD_CFLAGS DEBUG="FALSE"> -O2  </ADD_CFLAGS>
   <NETCDF_PATH>$(NETCDFROOT)</NETCDF_PATH>
   <PNETCDF_PATH>$(PNETCDFROOT)</PNETCDF_PATH>
+  <MPI_PATH MPILIB="openmpi">/opt/openmpi-1.8-intel</MPI_PATH>
   <ESMF_LIBDIR>/projects/ccsm/esmf-6.3.0rp1/lib/libO/Linux.intel.64.openmpi.default</ESMF_LIBDIR>
   <CONFIG_ARGS> --host=Linux </CONFIG_ARGS>
   <ADD_SLIBS> $(shell $(NETCDF_PATH)/bin/nf-config --flibs) -L/projects/ccsm/BLAS-intel -lblas_LINUX</ADD_SLIBS>
   <PIO_FILESYSTEM_HINTS>lustre </PIO_FILESYSTEM_HINTS>
-  <ADD_SLIBS MPILIB="mpich"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mpich2"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mpt"> -mkl=cluster </ADD_SLIBS>
   <ADD_SLIBS MPILIB="openmpi"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mvapich"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="impi"> -mkl=cluster </ADD_SLIBS>
   <ADD_SLIBS MPILIB="mpi-serial"> -mkl </ADD_SLIBS>
   <ALBANY_PATH>/projects/ccsm/AlbanyTrilinos/Albany/build/install</ALBANY_PATH>
 </compiler>
@@ -663,12 +659,7 @@ for mct, etc.
   <CONFIG_ARGS> --host=Linux </CONFIG_ARGS>
   <ADD_SLIBS> $(shell $(NETCDF_PATH)/bin/nf-config --flibs) -L/projects/ccsm/BLAS-intel -lblas_LINUX</ADD_SLIBS>
   <PIO_FILESYSTEM_HINTS>lustre </PIO_FILESYSTEM_HINTS>
-  <ADD_SLIBS MPILIB="mpich"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mpich2"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mpt"> -mkl=cluster </ADD_SLIBS>
   <ADD_SLIBS MPILIB="openmpi"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="mvapich"> -mkl=cluster </ADD_SLIBS>
-  <ADD_SLIBS MPILIB="impi"> -mkl=cluster </ADD_SLIBS>
   <ADD_SLIBS MPILIB="mpi-serial"> -mkl </ADD_SLIBS>
   <ALBANY_PATH>/projects/ccsm/AlbanyTrilinos/Albany/build/install</ALBANY_PATH>
 </compiler>

cime_config/acme/machines/config_machines.xml

@@ -378,7 +378,7 @@
     </module_system>
     <environment_variables>
       <env name="NETCDFROOT">$SEMS_NETCDF_ROOT</env>
-      <env name="PNETCDFROOT">$SEMS_NETCDF_ROOT</env>
+      <env name="PNETCDFROOT" mpilib="!mpi-serial">$SEMS_NETCDF_ROOT</env>
     </environment_variables>
 </machine>