Fix dg-prune-output regex for versioned namespace

[François Dumont]

Some tests dg-prune-output regex need to be adapted to pass when 
versioned namespace is activated.

I preferred to add the version namespace in the regex rather than 
removing namespace qualification. Let me know if you would prefer the 
other approach.

    * testsuite/23_containers/deque/48101_neg.cc: Add optional version
    namespace in dg-prune-output regex.
    * testsuite/23_containers/vector/48101_neg.cc: Likewise.
    * testsuite/27_io/filesystem/path/io/dr2989.cc: Likewise.

Tested under Linux x86_64 with and without versioned namespace.

Ok to commit ?

François

diff --git a/libstdc++-v3/testsuite/23_containers/deque/48101_neg.cc b/libstdc++-v3/testsuite/23_containers/deque/48101_neg.cc
index 1f9e3e3b932..6f5a648e059 100644
--- a/libstdc++-v3/testsuite/23_containers/deque/48101_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/deque/48101_neg.cc
@@ -26,5 +26,5 @@ test01()
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
-// { dg-prune-output "std::allocator<.* has no member named " }
+// { dg-prune-output "std::(__8::)?allocator<.* has no member named " }
 // { dg-prune-output "must have the same value_type as its allocator" }
diff --git a/libstdc++-v3/testsuite/23_containers/vector/48101_neg.cc b/libstdc++-v3/testsuite/23_containers/vector/48101_neg.cc
index 620170d0a15..709fc7e1649 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/48101_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/48101_neg.cc
@@ -26,5 +26,5 @@ test01()
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
-// { dg-prune-output "std::allocator<.* has no member named " }
+// { dg-prune-output "std::(__8::)?allocator<.* has no member named " }
 // { dg-prune-output "must have the same value_type as its allocator" }
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/path/io/dr2989.cc b/libstdc++-v3/testsuite/27_io/filesystem/path/io/dr2989.cc
index b9a1235e1fe..72eedf50d21 100644
--- a/libstdc++-v3/testsuite/27_io/filesystem/path/io/dr2989.cc
+++ b/libstdc++-v3/testsuite/27_io/filesystem/path/io/dr2989.cc
@@ -32,4 +32,4 @@ void foo(std::iostream& s) {
   s << p; // { dg-error "no match" }
   s >> p; // { dg-error "no match" }
 }
-// { dg-prune-output "no type .* std::enable_if" }
+// { dg-prune-output "no type .* std::(__8::)?enable_if" }