build: Use mold linker with gcc instead of clang

Since the rust-stable Flatpak extension now supports it. This way we
don't need to depend on the llvm Flatpak extension, which simplifies
the configuration.

.gitlab-ci/test.yml

@@ -59,6 +59,8 @@ build-docs:
     # We want to use the nightly toolchain inside the build terminal.
     - sed -i 's|"org.freedesktop.Sdk.Extension.rust-stable"|"org.freedesktop.Sdk.Extension.rust-nightly"|g' ${MANIFEST_PATH}
     - sed -i 's|/rust-stable/bin|/rust-nightly/extra/sdk/rust-nightly/bin|g' ${MANIFEST_PATH}
+    # Do not use the mold linker because it doesn't work with the rust-nightly extension at the moment
+    - sed -i 's|-C link-arg=-fuse-ld=mold||g' ${MANIFEST_PATH}
     - flatpak-builder --keep-build-dirs --user --disable-rofiles-fuse --stop-at=${FLATPAK_MODULE} flatpak_app --repo=repo ${BRANCH:+--default-branch=$BRANCH} ${MANIFEST_PATH}
     - echo "ninja src/doc" | flatpak-builder --disable-rofiles-fuse --build-shell=${FLATPAK_MODULE} flatpak_app ${MANIFEST_PATH}
     - tar --auto-compress --create --file "${CI_PROJECT_DIR}/${CI_PROJECT_NAME}-docs.tar.gz" --directory ".flatpak-builder/build/${FLATPAK_MODULE}/_flatpak_build/cargo-target/doc" .

.gitlab-ci/utils.yml

@@ -18,17 +18,12 @@
 # Update the Flatpak manifest to use the latest stable GNOME runtime and use the corresponding
 # container image.
 #
-# To get a list of available GNOME and LLVM versions, see:
+# To get a list of available GNOME versions, see:
 # https://gitlab.gnome.org/GNOME/gnome-runtime-images/-/blob/master/.gitlab-ci.yml
 .stable_runtime:
   image: 'quay.io/gnome_infrastructure/gnome-runtime-images:gnome-${GNOME_STABLE_VERSION}'
   variables:
     GNOME_STABLE_VERSION: "49"
-    FREEDESKTOP_RUNTIME_BRANCH: "25.08"
-    LLVM_NIGHTLY_VERSION: "20"
-    LLVM_STABLE_VERSION: "20"
   before_script:
     # We want to use the latest stable GNOME runtime instead of the nightly runtime.
     - sed -i "s|master|${GNOME_STABLE_VERSION}|g" ${MANIFEST_PATH}
-    # We want to use the latest LLVM extension for the stable runtime.
-    - sed -i "s|llvm${LLVM_NIGHTLY_VERSION}|llvm${LLVM_STABLE_VERSION}|g" ${MANIFEST_PATH}

CONTRIBUTING.md

@@ -22,16 +22,17 @@ can also provide general help about using Rust in GNOME.
 
 ### Prerequisites
 
-Fractal is written in Rust, so you will need to have at least Rust 1.80 and Cargo available on your
+Fractal is written in Rust, so you will need to have at least Rust (the minimum required version is
-system. You will also need to install the Rust nightly toolchain to be able to run our
+available in the `Cargo.toml` file as `package.rust-version`) and Cargo available on your system.
+You will also need to install the Rust nightly toolchain to be able to run our
 [pre-commit hook](#pre-commit), which can be done with:
 
 ```sh
 rustup toolchain install nightly
 ```
 
-If you're building Fractal with Flatpak (via GNOME Builder or the command line), you will need to
+If you are building Fractal with Flatpak (via GNOME Builder or the command line), you will need to
-manually add the necessary remotes and install the required freedesktop.org extensions:
+manually add the necessary remotes and install the Rust freedesktop.org extension:
 
 ```sh
 # Add Flathub and the gnome-nightly repo
@@ -43,9 +44,6 @@ flatpak install --user gnome-nightly org.gnome.Sdk//master org.gnome.Platform//m
 
 # Install the required rust-stable extension from Flathub
 flatpak install --user flathub org.freedesktop.Sdk.Extension.rust-stable//25.08
-
-# Install the required llvm extension from Flathub
-flatpak install --user flathub org.freedesktop.Sdk.Extension.llvm20//25.08
 ```
 
 If you are building the flatpak manually you will also need flatpak-builder on your system, or the

build-aux/org.gnome.Fractal.Devel.json

@@ -4,8 +4,7 @@
     "runtime-version": "master",
     "sdk": "org.gnome.Sdk",
     "sdk-extensions": [
-        "org.freedesktop.Sdk.Extension.rust-stable",
+        "org.freedesktop.Sdk.Extension.rust-stable"
-        "org.freedesktop.Sdk.Extension.llvm20"
     ],
     "command": "fractal",
     "finish-args": [
@@ -20,13 +19,9 @@
         "--env=RUST_BACKTRACE=1"
     ],
     "build-options": {
-        "append-ld-library-path": "/usr/lib/sdk/llvm20/lib",
+        "append-path": "/usr/lib/sdk/rust-stable/bin",
-        "append-path": "/usr/lib/sdk/llvm20/bin:/usr/lib/sdk/rust-stable/bin",
         "env": {
-            "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER": "clang",
+            "RUSTFLAGS": "-C link-arg=-fuse-ld=mold --cfg=ruma_identifiers_storage=\"Arc\""
-            "CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS": "-C force-frame-pointers=yes -C link-arg=-fuse-ld=/usr/lib/sdk/rust-stable/bin/mold --cfg=ruma_identifiers_storage=\"Arc\"",
-            "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER": "clang",
-            "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUSTFLAGS": "-C force-frame-pointers=yes -C link-arg=-fuse-ld=/usr/lib/sdk/rust-stable/bin/mold --cfg=ruma_identifiers_storage=\"Arc\""
         },
         "build-args": [
             "--share=network"