fix: declare missing RPC build dependencies

[ZedingZhang]

Fixes #89.

Why

configure.ac unconditionally requires the libtirpc headers and library, but neither package recipe declared the corresponding development package. A clean build root created from those recipes therefore cannot satisfy the configure checks.

While validating the RPM change in a clean Rocky 8 container, configure advanced past libtirpc and exposed the same metadata drift for the required libnsl check. volcinstall.sh already installs libnsl2-devel on Rocky, but the RPM spec did not declare it.

What changed

• Add libtirpc-dev to Debian Build-Depends.
• Add libtirpc-devel to RPM BuildRequires.
• Add libnsl2-devel for RHEL-family version 8 and newer, while keeping the existing CentOS 6/7 dependency set intact.

Validation

Clean-container validation passed in both jobs:

• Ubuntu 20.04: parsed and installed debian/control build dependencies, ran dpkg-checkbuilddeps, ./bootstrap.sh, make -j2, and make check.
• Rocky 8: parsed and installed the spec's BuildRequires, then ran ./bootstrap.sh, make -j2, and make check.

The validation commit used the exact final contents of debian/control and spec/volclava.spec; its temporary workflow is intentionally excluded from this PR.

[CLAassistant]

All committers have signed the CLA.

[qinan-cn]

Starting from version 2.32, glibc removed the built-in Sun RPC, which is now provided by the standalone libtirpc library. For Ubuntu:
Ubuntu ｜ Version ｜ glibc Version ｜ xdr.h SourcePath
———————————————————————————————————————
20.04 and earlier ｜≤ 2.31 ｜libc6-dev ｜/usr/include/rpc/xdr.h
———————————————————————————————————————
21.10 / 22.04 / 24.04｜≥ 2.34 ｜libtirpc-dev ｜/usr/include/tirpc/rpc/xdr.h

I think we need to consider compatibility both in low version and high Ubuntu version for libtirpc-dev. e.g. adding dependency checking in volcinstall.sh instead of here. Please let Mingze give more reviewing.

[ZedingZhang]

Thanks, this is a good catch. I ran a clean Ubuntu 20.04/22.04/24.04 matrix to verify the boundary rather than assuming one dependency set works everywhere: https://github.com/ZedingZhang/volclava/actions/runs/33379130227

• 20.04 / glibc 2.31: libc6-dev owns /usr/include/rpc/xdr.h; configure, build, and tests pass without libtirpc-dev.
• 22.04 / glibc 2.35: the base toolchain currently pulls libnsl-dev and libtirpc-dev through libc6-dev, so the build also passes without a direct addition here.
• 24.04 / glibc 2.39: the base toolchain no longer provides either RPC header. Configure first fails on rpc/xdr.h; adding only libtirpc-dev then fails on the required libnsl check; adding libnsl-dev as well completes configure, make, and make check.

So I agree that an unconditional libtirpc-dev in debian/control is redundant for the supported 20.04 environment and incomplete for 24.04.

If DEB package builds remain 20.04-only, my proposed revision is to remove this Debian metadata change and update volcinstall.sh after installing the base Ubuntu development packages: when /usr/include/rpc/xdr.h is absent, install both libtirpc-dev and libnsl-dev. I would also limit both standalone RPM development packages to RHEL-family 8+ so CentOS 6/7 keep using their built-in interfaces.

If newer Ubuntu DEB build roots are intended to be supported too, the package recipe instead needs version-aware alternatives for both libtirpc and libnsl. I will wait for @limingze-ste's preference before changing the PR direction.

[ZedingZhang]

I also prepared the installer-based revision on a separate validation branch and tested it before touching this PR: https://github.com/ZedingZhang/volclava/actions/runs/33379779430

All four jobs pass: Ubuntu 20.04 keeps the built-in RPC path without installing the standalone packages; 22.04 and 24.04 install/retain both required development packages and complete the build/tests; the RPM job verifies the dependencies are absent when the spec is evaluated as EL7, present on EL8, and completes the Rocky 8 build. The revision is ready to apply once the intended DEB support scope is confirmed.

[qinan-cn]

see comments