openEuler 24.03 LTS native build inputs

This source supplies a build prerequisite for the native perl-DBD-Pg checks.
The dependency repository does not select a PostgreSQL server for the normal
xCAT/xCATsn closure. PostgreSQL backend runtime qualification is separate.

Source RPM:
https://repo.openeuler.org/openEuler-24.03-LTS/source/Packages/postgresql-15.6-1.oe2403.src.rpm
SHA256: 0e1dd792cccf353f7a0d7f3f9d13b1a22a7ace0a428f4b197193b99c58081960

Publisher key:
https://repo.openeuler.org/openEuler-24.03-LTS/source/RPM-GPG-KEY-openEuler
Fingerprint: 8AA16BF9F2CA5244010DCA963B477C60B675600B

Verify the source RPM checksum, signature, and payload digests before extraction.
Apply postgresql-15.6-openeuler-llvmjit-buildrequires.patch with patch -p1
from the directory containing the extracted postgresql.spec.

The patch makes the clang BuildRequires follow the existing llvmjit option.
PostgreSQL uses clang to generate LLVM bitcode. Its normal C compiler selection
uses gcc or cc, and its LLVM build paths are disabled when llvmjit is zero.
JIT-enabled BuildRequires remain unchanged.

Use the native openEuler build environment and these existing vendor options:

    --define 'llvmjit 0' --define 'external_libpq 0'
    --define 'runselftest 1' --define 'test 1'

Keep the other vendor feature defaults, including SSL, GSSAPI, LDAP, PAM,
SELinux, ICU, UUID, and procedural languages. Build as an unprivileged user;
the regression tests require this. Retain the regression, contrib, procedural
language, and postgresql-setup tests. Resolve all remaining BuildRequires from
signed native packages before building.

Use the vendor-default private libpq build. Its libraries have private SONAMEs.
The external_libpq=1 branch in this SRPM has a stale patch that fails during
normal preparation. Build DBD-Pg with the vendor libpq-devel package;
postgresql-private-devel declares a conflict with that package.

On ppc64le, use mock-configs/openeuler-24.03-ppc64le.cfg when invoking the
existing mock build owner. The downloaded source RPM and generated packages
are external build artifacts. This directory does not add a package builder.

After building, verify package Provides/Requires, native architecture, and
libpq linkage. Build the matching native DBD-Pg source RPM without changes:

https://repo.openeuler.org/openEuler-24.03-LTS/source/Packages/perl-DBD-Pg-3.18.0-1.oe2403.src.rpm
SHA256: 5bb91b28459ee5754c031cf62471c86a887392587c261c8df61ab44e4c8caf09

Retain its make test check. Validate xCAT schema initialization, SQL
transactions, authentication, backup/restore, and reconnect behavior before
using the resulting packages for management or service nodes.