Fail to Build with glibc 2.43 due to ISO C23 const return types

[polkorny]

Hello Ronnie!

The libsmb2 package currently fails to build when linked against glibc 2.43 in Debian.

This was observed during the Debian glibc 2.43 rebuilds:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1128682

Full build logs (arm64) are available at:
https://people.debian.org/~ema/glibc-2.43-rebuilds/output-1/libsmb2_arm64.build

Please let me know if you need additional information or testing.