patch 8.1.0766: various problems when using Vim on VMS

Problem:    Various problems when using Vim on VMS.
Solution:   Various fixes. Define long_long_T. (Zoltan Arpadffy)
diff --git a/src/fileio.c b/src/fileio.c
index 0608625..f6a7995 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -5334,14 +5334,14 @@
 	*p++ = ' ';
     if (shortmess(SHM_LINES))
 	vim_snprintf((char *)p, IOSIZE - (p - IObuff),
-		"%ldL, %lldC", lnum, (long long)nchars);
+		"%ldL, %lldC", lnum, (long_long_T)nchars);
     else
     {
 	sprintf((char *)p, NGETTEXT("%ld line, ", "%ld lines, ", lnum), lnum);
 	p += STRLEN(p);
 	vim_snprintf((char *)p, IOSIZE - (p - IObuff),
 		NGETTEXT("%lld character", "%lld characters", nchars),
-		(long long)nchars);
+		(long_long_T)nchars);
     }
 }