Consolidation with CDI-PIO (develop)

Generally, this is !11 (merged) rebased onto the develop branch.

This is the first develop-based version accepted by the Buildbot of ICON: https://buildbot.dkrz.de/grid?branch=m300488/cdi-pio-2-integration

examples/Makefile.am

@@ -53,10 +53,12 @@ cdi_write_f2003_SOURCES = cdi_write_f2003.f90
 cdi_write_f2003_LDADD = $(top_builddir)/src/libcdi_f2003.la
 
 if FC_MOD_UPPERCASE
-cdi_read_f2003.$(OBJEXT) cdi_write_f2003.$(OBJEXT): $(top_builddir)/src/MO_CDI.$(FCMODEXT)
-else
-cdi_read_f2003.$(OBJEXT) cdi_write_f2003.$(OBJEXT): $(top_builddir)/src/mo_cdi.$(FCMODEXT)
-endif
+mo_cdi_mod = MO_CDI.$(FCMODEXT)
+else !FC_MOD_UPPERCASE
+mo_cdi_mod = mo_cdi.$(FCMODEXT)
+endif !FC_MOD_UPPERCASE
+
+cdi_read_f2003.$(OBJEXT) cdi_write_f2003.$(OBJEXT): $(top_builddir)/src/$(mo_cdi_mod)
 
 clean-local:
 	-rm -rf *.dSYM