patch 9.0.1921: not possible to use the jumplist like a stack

Problem:  not possible to use the jumplist like a stack
Solution: Add the 'jumpoptions' setting to make the jumplist
          a stack.

Add an option for using jumplist like tag stack

related: #7738
closes: #13134

ported from NeoVim:

- https://neovim.io/doc/user/motion.html#jumplist-stack
- neovim/neovim@39094b3
- neovim/neovim#11530
- https://vi.stackexchange.com/questions/18344/how-to-change-jumplist-behavior

Based on the feedback in the previous PR, it looks like many people like
this option.

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Co-authored-by: butwerenotthereyet <58348703+butwerenotthereyet@users.noreply.github.com>
diff --git a/src/option.h b/src/option.h
index 3bd2eb9..6874830 100644
--- a/src/option.h
+++ b/src/option.h
@@ -601,6 +601,9 @@
 EXTERN int	p_fs;		// 'fsync'
 #endif
 EXTERN int	p_gd;		// 'gdefault'
+EXTERN char_u	*p_jop;		// 'jumpoptions'
+EXTERN unsigned	jop_flags;	//
+#define JOP_STACK		0x001
 #ifdef FEAT_PROP_POPUP
 # ifdef FEAT_QUICKFIX
 EXTERN char_u	*p_cpp;		// 'completepopup'