[gcc r14-7916] gccrs: Add missing CHECKING_P guard to rust-punycode.cc

[Arthur Cohen]

https://gcc.gnu.org/g:0ebb0a75b40275fe80b8084a2854471437b1f195

commit r14-7916-g0ebb0a75b40275fe80b8084a2854471437b1f195
Author: Owen Avery <powerboat9.gamer@gmail.com>
Date:   Fri Aug 11 22:39:57 2023 -0400

    gccrs: Add missing CHECKING_P guard to rust-punycode.cc
    
    gcc/rust/ChangeLog:
    
            * util/rust-punycode.cc: Add CHECKING_P guard.
    
    Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

Diff:
---
 gcc/rust/util/rust-punycode.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/rust/util/rust-punycode.cc b/gcc/rust/util/rust-punycode.cc
index 6c796ab794f..8da724cc65e 100644
--- a/gcc/rust/util/rust-punycode.cc
+++ b/gcc/rust/util/rust-punycode.cc
@@ -150,6 +150,8 @@ encode_punycode (const Utf8String &input)
 
 } // namespace Rust
 
+#if CHECKING_P
+
 namespace selftest {
 
 void
@@ -176,3 +178,5 @@ rust_punycode_encode_test ()
 }
 
 } // namespace selftest
+
+#endif // CHECKING_P