[gcc r13-4467] driver: fix validate_switches logic

[gcc r13-4467] driver: fix validate_switches logic

[Jason Merrill]

https://gcc.gnu.org/g:6d3c634c8baebd9ff12c39d61947752486758bd3

commit r13-4467-g6d3c634c8baebd9ff12c39d61947752486758bd3
Author: Jason Merrill <jason@redhat.com>
Date:   Sun Nov 27 14:30:14 2022 -0500

    driver: fix validate_switches logic
    
    Under the old logic for validate_switches, once suffix or starred got set,
    they stayed set for all later switches found in the spec.  So for e.g.
    
    %{g*:%{%:debug-level-gt(0):
    
    Once we see g*, starred is set.  Then we see %:, and it sees that as a
    zero-length switch, which because starred is still set, matches any and all
    command-line options.  So targets that use such a spec accept all options in
    the driver, while ones that don't reject some, such as the recent
    -nostdlib++.
    
    This patch fixes the inconsistency, so all targets would complain about
    -nostdlib++, and then sets SKIPOPT for it so they don't.
    
    gcc/ChangeLog:
    
            * gcc.cc (validate_switches): Reset suffix/starred on loop.
    
    gcc/cp/ChangeLog:
    
            * g++spec.cc (lang_specific_driver): Set SKIPOPT for nostdlib++.

Diff:
---
 gcc/cp/g++spec.cc | 4 +++-
 gcc/gcc.cc        | 7 +++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/gcc/cp/g++spec.cc b/gcc/cp/g++spec.cc
index e599ac906f6..3d3b042dd56 100644
--- a/gcc/cp/g++spec.cc
+++ b/gcc/cp/g++spec.cc
@@ -167,8 +167,10 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
 	  need_experimental = true;
 	  break;
 
-	case OPT_nostdlib:
 	case OPT_nostdlib__:
+	  args[i] |= SKIPOPT;
+	  /* FALLTHRU */
+	case OPT_nostdlib:
 	case OPT_nodefaultlibs:
 	  library = -1;
 	  break;
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index ca1c9e27a94..2278e2b6bb1 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -9299,12 +9299,15 @@ validate_switches (const char *start, bool user_spec, bool braced)
   const char *atom;
   size_t len;
   int i;
-  bool suffix = false;
-  bool starred = false;
+  bool suffix;
+  bool starred;
 
 #define SKIP_WHITE() do { while (*p == ' ' || *p == '\t') p++; } while (0)
 
 next_member:
+  suffix = false;
+  starred = false;
+
   SKIP_WHITE ();
 
   if (*p == '!')