--- mstools/h/dos.h	2018/08/09 18:20:01	1.1
+++ mstools/h/dos.h	2018/08/09 18:21:09	1.1.1.3
@@ -1,7 +1,7 @@
 /***
 *dos.h - definitions for MS-DOS interface routines
 *
-*	Copyright (c) 1985-1991, Microsoft Corporation. All rights reserved.
+*	Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
 *
 *Purpose:
 *	Defines the structs and unions used for the direct DOS interface
@@ -18,12 +18,40 @@ extern "C" {
 #endif
 
 
-#if (_MSC_VER <= 600)
-#define __cdecl _cdecl
+/*
+ * Conditional macro definition for function calling type and variable type
+ * qualifiers.
+ */
+#if   ( (_MSC_VER >= 800) && (_M_IX86 >= 300) )
+
+/*
+ * Definitions for MS C8-32 (386/486) compiler
+ */
+#define _CRTAPI1 __cdecl
+#define _CRTAPI2 __cdecl
+
+#elif ( _MSC_VER == 600 )
+
+/*
+ * Definitions for old MS C6-386 compiler
+ */
+#define _CRTAPI1 _cdecl
+#define _CRTAPI2 _cdecl
+#define _M_IX86  300
+
+#else
+
+/*
+ * Other compilers (e.g., MIPS)
+ */
+#define _CRTAPI1
+#define _CRTAPI2
+
 #endif
 
 
 
+
 /* _getdiskfree structure (duplicated in DIRECT.H) */
 
 #ifndef _DISKFREE_T_DEFINED
@@ -52,17 +80,49 @@ struct _diskfree_t {
 
 /* external variable declarations */
 
-extern unsigned int _osversion;
+#if  defined(_WIN32_) || defined(_POSIX_)
+
+#ifdef	_DLL
 
+#define _osversion   (*_osversion_dll)
+#define _osmajor     (*_osmajor_dll)
+#define _osminor     (*_osminor_dll)
+#define _baseversion (*_baseversion_dll)
+#define _basemajor   (*_basemajor_dll)
+#define _baseminor   (*_baseminor_dll)
+#define _pgmptr      (*_pgmptr_dll)
+
+extern unsigned int * _osversion_dll;
+extern unsigned int * _osmajor_dll;
+extern unsigned int * _osminor_dll;
+extern unsigned int * _baseversion_dll;
+extern unsigned int * _basemajor_dll;
+extern unsigned int * _baseminor_dll;
+extern char ** _pgmptr_dll;
+
+#else
+
+
+extern unsigned int _osversion;
 extern unsigned int _osmajor;
 extern unsigned int _osminor;
 extern unsigned int _baseversion;
 extern unsigned int _basemajor;
 extern unsigned int _baseminor;
+extern char * _pgmptr;
+
+#endif
+
+#else	/* ndef (_WIN32_ || _POSIX_) */
+
+extern unsigned int _osversion;
+
+#endif /* _WIN32_ */
+
 
 /* function prototypes */
 
-unsigned _getdiskfree(unsigned, struct _diskfree_t *);
+unsigned _CRTAPI1 _getdiskfree(unsigned, struct _diskfree_t *);
 
 #if !__STDC__
 /* Non-ANSI name for compatibility */