NAME
	RunCommand -- Runs a program using the current process (V36)

   SYNOPSIS
	rc = RunCommand(seglist, stacksize, argptr, argsize)
	D0                D1         D2       D3      D4

	LONG RunCommand(BPTR, ULONG, STRPTR, ULONG)

   FUNCTION
	Runs a command on your process/cli.  Seglist may be any language,
	including BCPL programs.  Stacksize is in bytes.  argptr is a null-
	terminated string, argsize is its length.  Returns the returncode the
	program exited with in d0. Returns -1 if the stack couldn't be
	allocated.

	NOTE: the argument string MUST be terminated with a newline to work
	properly with ReadArgs() and other argument parsers.

	RunCommand also takes care of setting up the current input filehandle
	in such a way that ReadArgs() can be used in the program, and restores
	the state of the buffering before returning.  It also sets the value
	returned by GetArgStr(), and restores it before returning.  NOTE:
	the setting of the argument string in the filehandle was added in V37.

	It's usually appropriate to set the command name (via
	SetProgramName()) before calling RunCommand().  RunCommand() sets
	the value returned by GetArgStr() while the command is running.

   INPUTS
	seglist   - Seglist of command to run.
	stacksize - Number of bytes to allocate for stack space
	argptr    - Pointer to argument command string.
	argsize   - Number of bytes in argument command.

   RESULT
	rc        - Return code from executed command. -1 indicates failure

   SEE ALSO
	CreateNewProc(), SystemTagList(), Execute(), GetArgStr(),
	SetProgramName(), ReadArgs()