This update for postgresql16 fixes the following issues:

Upgraded to 16.11:

- CVE-2025-12817: Fixed missing check for CREATE privileges on the schema in CREATE STATISTICS (bsc#1253332)
- CVE-2025-12818: Fixed integer overflow in allocation-size calculations within libpq (bsc#1253333)
  
Other fixes:

- Use %product_libs_llvm_ver to determine the LLVM version.
- Remove conditionals for obsolete PostgreSQL releases.
- Sync spec file from version 18.