[gcc r16-5494] libstdc++: Include <ostream> in <regex> for debug mode

[Jonathan Wakely]

https://gcc.gnu.org/g:e8cf136b1a281db54edf5f824e8b08e5b757269f

commit r16-5494-ge8cf136b1a281db54edf5f824e8b08e5b757269f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Nov 21 12:02:54 2025 +0000

    libstdc++: Include <ostream> in <regex> for debug mode
    
    I don't know what changed, but I'm seeing some new failures:
    
    FAIL: 23_containers/vector/capacity/114945.cc  -std=gnu++11 (test for excess errors)
    FAIL: 23_containers/vector/capacity/114945.cc  -std=gnu++14 (test for excess errors)
    FAIL: 23_containers/vector/capacity/114945.cc  -std=gnu++17 (test for excess errors)
    FAIL: 28_regex/basic_regex/85098.cc  -std=gnu++11 (test for excess errors)
    FAIL: 28_regex/basic_regex/85098.cc  -std=gnu++14 (test for excess errors)
    FAIL: 28_regex/basic_regex/85098.cc  -std=gnu++17 (test for excess errors)
    FAIL: 28_regex/simple_c++11.cc   (test for excess errors)
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/regex_automaton.tcc [_GLIBCXX_DEBUG]: Include
            <ostream> so that _State_base::_M_print etc. can use it.

Diff:
---
 libstdc++-v3/include/bits/regex_automaton.tcc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libstdc++-v3/include/bits/regex_automaton.tcc b/libstdc++-v3/include/bits/regex_automaton.tcc
index 8a826469db10..4d566c62ecdd 100644
--- a/libstdc++-v3/include/bits/regex_automaton.tcc
+++ b/libstdc++-v3/include/bits/regex_automaton.tcc
@@ -28,6 +28,10 @@
  *  Do not attempt to use it directly. @headername{regex}
  */
 
+#ifdef _GLIBCXX_DEBUG
+# include <ostream>
+#endif
+
 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION