Two small fixes for C/C++ lexer

[Zack Weinberg <zack at wolery dot cumb dot org>]

1) As previously discussed, adjust the #ifdefs so C++ specific pragmas
still work on targets that don't want #pragma pack, #pragma weak, etc.
This has been bootstrapped on i386-linux and I built cc1 and cc1plus in a
i386-linux->hppa-hpux10 cross configuration.

2) One line hopeful fix for bootstrap failures on targets that do not
define NO_IMPLICIT_EXTERN_C.  I tested this to the best of my
abilities by building a "native i386-sysv4" compiler on my linux box.
This is not the world's greatest test, but (a) the patch is Obviously
Correct, or at least can't make the situation worse; (b) if it's
wrong, the autobuilder will let me know about it in short order. :)

zw

	* c-pragma.c: Don't elide entire file if !HANDLE_GENERIC_PRAGMAS.
	(init_pragma): Avoid warning if pfile happens to be unused.
	* c-pragma.h: Never define HANDLE_GENERIC_PRAGMAS.  Never
	define init_pragma to nothing.  Always prototype
	init_pragma.  Prototype dispatch_pragma if !USE_CPPLIB.

	* c-lex.c (process_directive): Always call dispatch_pragma.
	Initialize entering_c_header to 0.

===================================================================
Index: c-pragma.c
--- c-pragma.c	2000/09/07 22:24:31	1.35
+++ c-pragma.c	2000/09/08 22:11:01
@@ -32,8 +32,6 @@ Boston, MA 02111-1307, USA.  */
 #include "c-lex.h"
 #include "tm_p.h"
 
-#ifdef HANDLE_GENERIC_PRAGMAS
-
 #if USE_CPPLIB
 extern cpp_reader parse_in;
 #else
@@ -438,10 +436,11 @@ dispatch_pragma ()
 void
 init_pragma ()
 {
+  cpp_reader *pfile ATTRIBUTE_UNUSED;
 #if !USE_CPPLIB
-  cpp_reader *pfile = 0;
+  pfile = 0;
 #else
-  cpp_reader *pfile = &parse_in;
+  pfile = &parse_in;
 #endif
 
 #ifdef HANDLE_PRAGMA_PACK
@@ -450,7 +449,6 @@ init_pragma ()
 #ifdef HANDLE_PRAGMA_WEAK
   cpp_register_pragma (pfile, 0, "weak", handle_pragma_weak);
 #endif
-
 #ifdef REGISTER_TARGET_PRAGMAS
   REGISTER_TARGET_PRAGMAS (pfile);
 #endif
@@ -460,5 +458,3 @@ init_pragma ()
 		mark_align_stack);
 #endif
 }
-
-#endif /* HANDLE_GENERIC_PRAGMAS */
===================================================================
Index: c-pragma.h
--- c-pragma.h	2000/09/07 22:24:31	1.16
+++ c-pragma.h	2000/09/08 22:11:01
@@ -57,25 +57,11 @@ extern struct weak_syms * weak_decls;
 extern int add_weak PARAMS ((const char *, const char *));
 #endif /* HANDLE_PRAGMA_WEAK */
 
-
-/* Define HANDLE_GENERIC_PRAGMAS if any kind of front-end pragma
-   parsing is to be done.  The code in GCC's generic C source files
-   will only look for the definition of this constant.  They will
-   ignore definitions of HANDLE_PRAGMA_PACK and so on.  */
-#if defined HANDLE_PRAGMA_PACK || defined HANDLE_PRAGMA_WEAK \
-    || defined REGISTER_TARGET_PRAGMAS
-#define HANDLE_GENERIC_PRAGMAS
-#endif
-
-#ifdef HANDLE_GENERIC_PRAGMAS
 extern void init_pragma PARAMS ((void));
 
-# if !USE_CPPLIB
+/* If cpplib is in use, it handles dispatch.  */
+#if !USE_CPPLIB
 extern void dispatch_pragma PARAMS ((void));
-# endif
-
-#else
-# define init_pragma()
 #endif
 
 /* Duplicate prototypes for the register_pragma stuff and the typedef for
===================================================================
Index: c-lex.c
--- c-lex.c	2000/09/08 01:38:08	1.99
+++ c-lex.c	2000/09/08 22:11:02
@@ -438,7 +438,7 @@ process_directive ()
   int action_number, l;
   char *new_file;
 #ifndef NO_IMPLICIT_EXTERN_C
-  int entering_c_header;
+  int entering_c_header = 0;
 #endif
   
   /* Don't read beyond this line.  */
@@ -457,9 +457,7 @@ process_directive ()
 
       if (!strcmp (name, "pragma"))
 	{
-#ifdef HANDLE_GENERIC_PRAGMAS
 	  dispatch_pragma ();
-#endif
 	  goto skipline;
 	}
       else if (!strcmp (name, "define"))