patch 8.1.1306: Borland support is outdated and doesn't work

Problem:    Borland support is outdated and doesn't work.
Solution:   Remove Borland support, there are other (free) compilers
            available. (Thomas Dziedzic, Ken Takata, closes #4364)
diff --git a/src/xxd/xxd.c b/src/xxd/xxd.c
index b9f6041..f2192cf 100644
--- a/src/xxd/xxd.c
+++ b/src/xxd/xxd.c
@@ -81,7 +81,7 @@
 #else
 # include <fcntl.h>
 #endif
-#if defined(WIN32) || defined(__BORLANDC__) || defined(CYGWIN)
+#if defined(WIN32) || defined(CYGWIN)
 # include <io.h>	/* for setmode() */
 #else
 # ifdef UNIX
@@ -96,12 +96,6 @@
 # include <unix.h>	/* for fdopen() on MAC */
 #endif
 
-#if defined(__BORLANDC__) && __BORLANDC__ <= 0x0410 && !defined(fileno)
-/* Missing define and prototype grabbed from the BC 4.0 <stdio.h> */
-# define fileno(f)       ((f)->fd)
-FILE   _FAR *_Cdecl _FARFUNC fdopen(int __handle, char _FAR *__type);
-#endif
-
 
 /*  This corrects the problem of missing prototypes for certain functions
  *  in some GNU installations (e.g. SunOS 4.1.x).
@@ -190,7 +184,7 @@
 #endif
 
 #ifndef __P
-# if defined(__STDC__) || defined(WIN32) || defined(__BORLANDC__)
+# if defined(__STDC__) || defined(WIN32)
 #  define __P(a) a
 # else
 #  define __P(a) ()