patch 8.2.1967: the session file does not restore the alternate file
Problem: The session file does not restore the alternate file.
Solution: Add ":balt". Works like ":badd" and also sets the buffer as the
alternate file. Use it in the session file. (closes #7269,
closes #6714)
diff --git a/src/vim.h b/src/vim.h
index 289ef3c..d2e22fe 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -1029,6 +1029,7 @@
#define ECMD_OLDBUF 0x04 // use existing buffer if it exists
#define ECMD_FORCEIT 0x08 // ! used in Ex command
#define ECMD_ADDBUF 0x10 // don't edit, just add to buffer list
+#define ECMD_ALTBUF 0x20 // like ECMD_ADDBUF and set the alternate file
// for lnum argument in do_ecmd()
#define ECMD_LASTL (linenr_T)0 // use last position in loaded file