patch 9.0.1001: classes are not documented or implemented yet

Problem:    Classes are not documented or implemented yet.
Solution:   Make the first steps at documenting Vim9 objects, classes and
            interfaces.  Make initial choices for the syntax.  Add a skeleton
            implementation.  Add "public" and "this" in the command table.
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index b559467..4261256 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -851,6 +851,7 @@
 	$(OUTDIR)/usercmd.o \
 	$(OUTDIR)/userfunc.o \
 	$(OUTDIR)/version.o \
+	$(OUTDIR)/vim9class.o \
 	$(OUTDIR)/vim9cmds.o \
 	$(OUTDIR)/vim9compile.o \
 	$(OUTDIR)/vim9execute.o \
@@ -1251,6 +1252,8 @@
 
 $(OUTDIR)/version.o: version.c $(INCL) version.h
 
+$(OUTDIR)/vim9class.o: vim9class.c $(INCL) vim9.h
+
 $(OUTDIR)/vim9cmds.o: vim9cmds.c $(INCL) vim9.h
 
 $(OUTDIR)/vim9compile.o: vim9compile.c $(INCL) vim9.h