PATCH: Guard uses of fork

[Mark Mitchell <mark@codesourcery.com>]

This patch uses the HAVE_WORKING_FORK and HAVE_WORKING_VFORK macros
appropriately to guard calls to these functions.  (These macros are
already being defined by autoconf; we just need to use them.)  I'm
checking HAVE_WORKING_FORK, even in the case of the call to vfork in
cli-cmds.c, because autoconf will "#define vfork fork" if there's no
vfork, but there is fork.  I left the CANT_FORK define in place
because that's defined by defs.h in the case __MSDOS__, and Dan says
that configure isn't run in that case.  I think it could safely be
removed (as surely, on __MSDOS__, nothing will define
HAVE_WORKING_[V]FORK, but I don't have a way of testing that.  I'm
happy to make that change as well, if people would like.

OK to apply?

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com

2005-03-09  Mark Mitchell  <mark@codesourcery.com>

	* utils.c (internal_vproblem): Guard call to fork with HAVE_FORK.
	* cli/cli-cmds.c (shell_escape): Guard call to vfork with
	HAVE_WORKING_VFORK and HAVE_WORKING_FORK. 

Index: utils.c
===================================================================
RCS file: /cvs/src/src/gdb/utils.c,v
retrieving revision 1.157
diff -c -5 -p -r1.157 utils.c
*** utils.c	24 Feb 2005 13:51:35 -0000	1.157
--- utils.c	10 Mar 2005 02:08:35 -0000
*************** further debugging may prove unreliable."
*** 787,798 ****
--- 787,800 ----
      }
    else
      {
        if (dump_core_p)
  	{
+ #ifdef HAVE_WORKING_FORK
  	  if (fork () == 0)
  	    abort ();		/* NOTE: GDB has only three calls to abort().  */
+ #endif
  	}
      }
  
    dejavu = 0;
  }
Index: cli/cli-cmds.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-cmds.c,v
retrieving revision 1.57
diff -c -5 -p -r1.57 cli-cmds.c
*** cli/cli-cmds.c	24 Feb 2005 13:51:36 -0000	1.57
--- cli/cli-cmds.c	10 Mar 2005 02:08:35 -0000
*************** echo_command (char *text, int from_tty)
*** 482,492 ****
  }
  
  static void
  shell_escape (char *arg, int from_tty)
  {
! #ifdef CANT_FORK
    /* If ARG is NULL, they want an inferior shell, but `system' just
       reports if the shell is available when passed a NULL arg.  */
    int rc = system (arg ? arg : "");
  
    if (!arg)
--- 482,493 ----
  }
  
  static void
  shell_escape (char *arg, int from_tty)
  {
! #if defined(CANT_FORK) || \
!       (!defined(HAVE_WORKING_VFORK) && !defined(HAVE_WORKING_FORK))
    /* If ARG is NULL, they want an inferior shell, but `system' just
       reports if the shell is available when passed a NULL arg.  */
    int rc = system (arg ? arg : "");
  
    if (!arg)