diff --git a/src/os_msdos.h b/src/os_msdos.h
new file mode 100644
index 0000000..576b238
--- /dev/null
+++ b/src/os_msdos.h
@@ -0,0 +1,106 @@
+/* vi:set ts=8 sts=4 sw=4:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ */
+
+/*
+ * MSDOS Machine-dependent things.
+ */
+
+#include "os_dos.h"		/* common MS-DOS and Win32 stuff */
+
+#define BINARY_FILE_IO
+#define USE_EXE_NAME		/* use argv[0] for $VIM */
+#define NO_COOKED_INPUT		/* mch_inchar() doesn't return whole lines */
+#define SYNC_DUP_CLOSE		/* sync() a file with dup() and close() */
+#define USE_TERM_CONSOLE
+#ifdef DJGPP
+# include <fcntl.h>		/* defines _USE_LFN */
+# define USE_LONG_FNAME _USE_LFN    /* decide at run time */
+# define USE_FNAME_CASE
+# define HAVE_PUTENV
+#else
+# define SHORT_FNAME		/* always 8.3 file name */
+#endif
+#define HAVE_STDLIB_H
+#define HAVE_STRING_H
+#define HAVE_FCNTL_H
+#define HAVE_STRCSPN
+#define HAVE_STRICMP
+#define HAVE_STRFTIME		/* guessed */
+#define HAVE_STRNICMP
+#define HAVE_MEMSET
+#define HAVE_QSORT
+#define HAVE_ST_MODE		/* have stat.st_mode */
+#if defined(__DATE__) && defined(__TIME__)
+# define HAVE_DATE_TIME
+#endif
+#define BREAKCHECK_SKIP	    1	/* call mch_breakcheck() each time, it's fast */
+#define HAVE_AVAIL_MEM
+
+/*
+ * Borland C++ 3.1 doesn't have _RTLENTRYF
+ */
+#ifdef __BORLANDC__
+# if __BORLANDC__ < 0x450
+#  define _RTLENTRYF
+# endif
+#endif
+
+#define FNAME_ILLEGAL "\"*?><|" /* illegal characters in a file name */
+
+#include <dos.h>
+#include <dir.h>
+#include <time.h>
+
+#ifdef DJGPP
+# include <unistd.h>
+# define HAVE_LOCALE_H
+# define setlocale(c, p)    djgpp_setlocale()
+#endif
+
+#ifndef DJGPP
+typedef long off_t;
+#endif
+
+/*
+ * Try several directories to put the temp files.
+ */
+#define TEMPDIRNAMES	"$TMP", "$TEMP", "c:\\TMP", "c:\\TEMP", ""
+#define TEMPNAMELEN	128
+
+#ifndef DFLT_MAXMEM
+# define DFLT_MAXMEM	256		/* use up to 256Kbyte for buffer */
+#endif
+#ifndef DFLT_MAXMEMTOT
+# define DFLT_MAXMEMTOT	0		/* decide in set_init */
+#endif
+
+#ifdef DJGPP
+# define BASENAMELEN  (_USE_LFN?250:8)	/* length of base of file name */
+#else
+# define BASENAMELEN	    8		/* length of base of file name */
+#endif
+
+/* codes for msdos mouse event */
+#define MSDOS_MOUSE_LEFT	0x01
+#define MSDOS_MOUSE_RIGHT	0x02
+#define MSDOS_MOUSE_MIDDLE	0x04
+
+#ifdef DJGPP
+int mch_rename(const char *OldFile, const char *NewFile);
+#else
+# define mch_rename(src, dst) rename(src, dst)
+#endif
+
+#ifdef DJGPP
+# define vim_mkdir(x, y) mkdir((char *)(x), y)
+#else
+# define vim_mkdir(x, y) mkdir((char *)(x))
+#endif
+#define mch_rmdir(x) rmdir((char *)(x))
+
+#define mch_setenv(name, val, x) setenv(name, val, x)