patch 8.0.0029
Problem:    Code for MS-Windows is complicated because of the exceptions for
            old systems.
Solution:   Drop support for MS-Windows older than Windows XP. (Ken Takata)
diff --git a/src/misc2.c b/src/misc2.c
index 4d914d2..030cff3 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -1420,7 +1420,7 @@
     length = (unsigned)STRLEN(string) + 3;  /* two quotes and a trailing NUL */
     for (p = string; *p != NUL; mb_ptr_adv(p))
     {
-# if defined(WIN32) || defined(DOS)
+# ifdef WIN32
 	if (!p_ssl)
 	{
 	    if (*p == '"')
@@ -1451,7 +1451,7 @@
 	d = escaped_string;
 
 	/* add opening quote */
-# if defined(WIN32) || defined(DOS)
+# ifdef WIN32
 	if (!p_ssl)
 	    *d++ = '"';
 	else
@@ -1460,7 +1460,7 @@
 
 	for (p = string; *p != NUL; )
 	{
-# if defined(WIN32) || defined(DOS)
+# ifdef WIN32
 	    if (!p_ssl)
 	    {
 		if (*p == '"')
@@ -1503,7 +1503,7 @@
 	}
 
 	/* add terminating quote and finish with a NUL */
-# if defined(WIN32) || defined(DOS)
+# ifdef WIN32
 	if (!p_ssl)
 	    *d++ = '"';
 	else