Patch to implement -Wunknown-pragmas

[Jeffrey A Law]

  In message <199710202210.PAA00478@elmo.cygnus.com>you write:
  > After all the discussion, here is the patch to implement the
  > -Wunknown-pragmas warning:
  > 
  > gcc/ChangeLog:
  > Mon Oct 20 10:43:15 1997  Nick Clifton  <nickc@cygnus.com>
  > 
  > 	* c-pragma.c (handle_pragma_token): Generate warning messages
  > 	about unknown pragmas if warn_unknown_pragmas is set.
  > 
  > 	* c-decl.c (c_decode_option): Parse -Wunknown-pragmas command
  > 	line option to set variable: warn_unknown_pragmas.
  > 
  > 	* invoke.texi (Warning Options): Document -Wunknown-pragmas
  > 	command line option.
  > 
  > gcc/cp/ChangeLog:
  > Mon Oct 20 10:36:44 1997  Nick Clifton  <nickc@cygnus.com>
  > 
  > 	* decl2.c (lang_decode_option): Add support for command line
  > 	option: -Wunknown-pragmas.
Just a minor note, I put a decl of warn_unknown_pragmas into flags.h
and installed your patch.

jeff