patch 8.1.2022: the option.c file is too big

Problem:    The option.c file is too big.
Solution:   Move option definitions to a separate file. (Yegappan Lakshmanan,
            closes #4918)
diff --git a/src/Makefile b/src/Makefile
index 34198ea..0efd88f7 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -3284,7 +3284,7 @@
 objects/ops.o: ops.c
 	$(CCC) -o $@ ops.c
 
-objects/option.o: option.c
+objects/option.o: option.c optiondefs.h
 	$(CCC_NF) $(LUA_CFLAGS) $(PERL_CFLAGS) $(PYTHON_CFLAGS) $(PYTHON3_CFLAGS) $(RUBY_CFLAGS) $(TCL_CFLAGS) $(ALL_CFLAGS) -o $@ option.c
 
 objects/os_beos.o: os_beos.c
@@ -3762,7 +3762,7 @@
 objects/option.o: option.c vim.h protodef.h auto/config.h feature.h os_unix.h \
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
- proto.h globals.h
+ proto.h globals.h optiondefs.h
 objects/os_unix.o: os_unix.c vim.h protodef.h auto/config.h feature.h os_unix.h \
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \