[gcc r16-5182] libstdc++: sync prune.exp with GCC

[Jason Merrill]

https://gcc.gnu.org/g:bc68e43df5fa1fad20151e3d0f841e2d920c7276

commit r16-5182-gbc68e43df5fa1fad20151e3d0f841e2d920c7276
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Nov 11 18:45:31 2025 +0530

    libstdc++: sync prune.exp with GCC
    
    I needed to add module context to dg-prune for libstdc++, and figured it
    made sense to sync it with the GCC version rather than maintain slightly
    different approaches to stripping the same messages.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/lib/prune.exp: Sync with gcc prune.exp.

Diff:
---
 libstdc++-v3/testsuite/lib/prune.exp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/testsuite/lib/prune.exp b/libstdc++-v3/testsuite/lib/prune.exp
index a9a29937e43a..93d3d526019b 100644
--- a/libstdc++-v3/testsuite/lib/prune.exp
+++ b/libstdc++-v3/testsuite/lib/prune.exp
@@ -53,12 +53,13 @@ proc libstdc++-dg-prune { system text } {
     regsub -all "(^|\n)\[^\n\]*:   (recursively )?required \[^\n\]*" $text "" text
     regsub -all "(^|\n)\[^\n\]*:   . skipping \[0-9\]* instantiation contexts \[^\n\]*" $text "" text
     regsub -all "(^|\n)\[^\n\]*:   in .constexpr. expansion \[^\n\]*" $text "" text
-    regsub -all "(^|\n)\[^\n\]*:   in requirements  .with\[^\n\]*" $text "" text
-    regsub -all "(^|\n)\[^\n\]*:   in requirements with\[^\n\]*" $text "" text
+    regsub -all "(^|\n)\[^\n\]*:   in requirements \[^\n\]*" $text "" text
     regsub -all "(^|\n)    inlined from \[^\n\]*" $text "" text
-    # Why doesn't GCC need these to strip header context?
-    regsub -all "(^|\n)In file included from \[^\n\]*" $text "" text
-    regsub -all "(^|\n)\[ \t\]*from \[^\n\]*" $text "" text
+
+    # Diagnostic inclusion stack
+    regsub -all "(^|\n)(In file)?\[ \]+included from \[^\n\]*" $text "" text
+    regsub -all "(^|\n)\[ \]+from \[^\n\]*" $text "" text
+    regsub -all "(^|\n)(In|of) module( \[^\n \]*,)? imported at \[^\n\]*" $text "" text
 
     # Ignore informational notes.
     #TODO As this isn't even using 'gcc-dg.exp', cannot consider its