tools: add shared current directory handle helper

Add tool_current_dhandle_only() as a small wrapper for callers that only need
the current NetWare directory handle.

Replace the local creator_current_dhandle() and tests_current_dhandle()
implementations in CREATOR and NWTESTS with the shared helper. This removes
duplicate requester-current-directory code without changing behavior.

creator.c

@@ -90,29 +90,6 @@ static void creator_usage(void)
   fprintf(stdout, "  CREATOR F:\\CIXTEST\\SUP\\S_SUP.TXT /ARCHIVE MARIO\n");
 }
 
-static int creator_get_current_drive(void)
-{
-  REGS regs;
-
-  regs.h.ah = 0x19;
-  int86(0x21, &regs, &regs);
-  return((int)regs.h.al);
-}
-
-static int creator_current_dhandle(uint8 *dhandle)
-{
-  uint8 connid = 0;
-  uint8 flags = 0;
-  int drive;
-
-  drive = creator_get_current_drive();
-  if (get_drive_info((uint8)drive, &connid, dhandle, &flags))
-    return(-1);
-  if (!connid || (flags & 0x80))
-    return(-1);
-  return(0);
-}
-
 static int hex_value(int c)
 {
   if (c >= '0' && c <= '9') return(c - '0');
@@ -516,7 +493,7 @@ int func_creator(int argc, char *argv[], int mode)
     return(1);
   }
 
-  if (creator_current_dhandle(&dhandle)) {
+  if (tool_current_dhandle_only(&dhandle)) {
     fprintf(stdout, "CREATOR: current drive is not a network drive\n");
     if (oldcwd[0]) chdir(oldcwd);
     return(1);