patch 8.1.1306: Borland support is outdated and doesn't work

Problem:    Borland support is outdated and doesn't work.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)

src/GvimExt/gvimext.cpp

@@ -16,14 +16,7 @@
 
 #include "gvimext.h"
 
-#ifdef __BORLANDC__
-# include <dir.h>
-# ifndef _strnicmp
-#  define _strnicmp(a, b, c) strnicmp((a), (b), (c))
-# endif
-#else
 static char *searchpath(char *name);
-#endif
 
 // Always get an error while putting the following stuff to the
 // gvimext.h file as class protected variables, give up and
@@ -917,7 +910,6 @@ BOOL CShellExt::LoadMenuIcon()
 	return TRUE;
 }
 
-#ifndef __BORLANDC__
     static char *
 searchpath(char *name)
 {
@@ -937,7 +929,6 @@ searchpath(char *name)
     }
     return (char *)"";
 }
-#endif
 
 STDMETHODIMP CShellExt::InvokeGvim(HWND hParent,
 				   LPCSTR  /* pszWorkingDir */,