GMP fails configuration in Freedesktop 25.08

[Antonio Romano]

Hello,

I'm trying to build libgccjit as a Flatpak module on top of Freedesktop
SDK 25.08. Building libgccjit and its dependencies on Freedesktop 24.08
works, as can be seen in this[*] Flatpak manifest for building the
org.gnu.Emacs flatpak with native compilation, but building it on
Freedesktop 25.08 fails due to an error occuring during GMP's
configuration.

[*] https://github.com/flathub/org.gnu.emacs/pull/74/commits


Here is a MVE for building GMP inside a Flatpak runtime.

**my-manifest.json**
```
{
  "id": "org.freedesktop.Sdk.Extension.gnu-gmp-test",
  "branch": "24.08",
  "runtime": "org.freedesktop.Platform",
  "runtime-version": "24.08",
  "sdk": "org.freedesktop.Sdk",
  "build-extension:": "true",
  "modules": [
    {
      "name": "gmp",
      "buildsystem": "autotools",
      "config-opts": [
        "--enable-static",
        "--disable-shared",
        "CFLAGS=-fPIC"
      ],
      "sources": [
        {
          "type": "archive",
          "url": "https://ftp.gnu.org/gnu/gmp/gmp-6.3.0.tar.xz",
          "sha256":
"a3c2b80201b89e68616f4ad30bc66aee4927c3ce50e33929ca819d5c43538898"
        }
      ]
    }
  ]
}
```

Build with flatpak-builder --force-clean  build-dir my-manifest.json

And it builds with no errors.

Replace "24.08" with "25.08" and I'll get the following error

```
=======================================================================
=
Building module gmp in /var/home/antonio/Code/org.gnu.gmp/.flatpak-
builder/build/gmp-3
=======================================================================
=
]2;flatpak-builder: Building gmpchecking build system type...
kabylake-pc-linux-gnu
checking host system type... kabylake-pc-linux-gnu
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking whether to enable maintainer-specific portions of Makefiles...
no
checking ABI=64
checking compiler gcc -fPIC ... no, long long reliability test 1
checking whether cc is gcc... yes
checking compiler cc -fPIC ... no, long long reliability test 1
checking ABI=x32
checking compiler gcc -fPIC ... no, long long reliability test 1
checking whether cc is gcc... yes
checking compiler cc -fPIC ... no, long long reliability test 1
checking ABI=32
checking compiler gcc -fPIC ... no, long long reliability test 1
checking compiler icc -fPIC ... no
checking whether cc is gcc... yes
checking compiler cc -fPIC ... no, long long reliability test 1
configure: error: could not find a working compiler, see config.log for
details
Error: module gmp: Child process exited with code 1

Compilation exited abnormally with code 1 at Wed Apr  1 18:40:42,
duration 2.72 s
```

The config.log file is sent as attachment.

As a desperate measure I combed through Fedora source rpm for
gpm-6.3.0-5.fc44[x], downloaded one of its downstream patches (which
you can find
as an attachment here) and tried to apply it but without success.

[x] https://koji.fedoraproject.org/koji/buildinfo?buildID=2899297


Any insights in this regard would be greatly appreciated. Thank you in
advance.
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