patch 7.4.1399
Problem:    The MS-DOS code does not build.
Solution:   Remove the old MS-DOS code.
diff --git a/src/option.h b/src/option.h
index 24e4184..2f1f04f 100644
--- a/src/option.h
+++ b/src/option.h
@@ -18,7 +18,7 @@
 #ifdef AMIGA
 # define DFLT_EFM	"%f>%l:%c:%t:%n:%m,%f:%l: %t%*\\D%n: %m,%f %l %t%*\\D%n: %m,%*[^\"]\"%f\"%*\\D%l: %m,%f:%l:%m,%f|%l| %m"
 #else
-# if defined(MSDOS) || defined(WIN3264)
+# if defined(WIN3264)
 #  define DFLT_EFM	"%f(%l) : %t%*\\D%n: %m,%*[^\"]\"%f\"%*\\D%l: %m,%f(%l) : %m,%*[^ ] %f %l: %m,%f:%l:%c:%m,%f(%l):%m,%f:%l:%m,%f|%l| %m"
 # else
 #  if defined(__EMX__)	/* put most common here (i.e. gcc format) at front */
@@ -386,10 +386,6 @@
 #ifdef FEAT_BROWSE
 EXTERN char_u	*p_bsdir;	/* 'browsedir' */
 #endif
-#ifdef MSDOS
-EXTERN int	p_biosk;	/* 'bioskey' */
-EXTERN int	p_consk;	/* 'conskey' */
-#endif
 #ifdef FEAT_LINEBREAK
 EXTERN char_u	*p_breakat;	/* 'breakat' */
 #endif
@@ -671,7 +667,7 @@
 #ifdef FEAT_MZSCHEME
 EXTERN long	p_mzq;		/* 'mzquantum */
 #endif
-#if defined(MSDOS) || defined(MSWIN)
+#if defined(MSWIN)
 EXTERN int	p_odev;		/* 'opendevice' */
 #endif
 EXTERN char_u	*p_opfunc;	/* 'operatorfunc' */
@@ -1074,9 +1070,7 @@
 #ifdef FEAT_SMARTINDENT
     , BV_SI
 #endif
-#ifndef SHORT_FNAME
     , BV_SN
-#endif
 #ifdef FEAT_SYN_HL
     , BV_SMC
     , BV_SYN