Commit 580ca121 for libheif

commit 580ca121af7cc4c608473159a6cf6b977d99e9e0
Author: Dirk Farin <dirk.farin@gmail.com>
Date:   Tue May 12 15:24:21 2026 +0200

    CI: compile with GCC 15

diff --git a/.github/workflows/gcc-versions.yml b/.github/workflows/gcc-versions.yml
index ecede0b8..df60ba84 100644
--- a/.github/workflows/gcc-versions.yml
+++ b/.github/workflows/gcc-versions.yml
@@ -14,6 +14,7 @@ jobs:
           - { NAME: "gcc-12", WITH_GRAPHICS: 1, WITH_X265: 1, WITH_AOM: 1, WITH_LIBDE265: 3, GCC: 12 }
           - { NAME: "gcc-13", WITH_GRAPHICS: 1, WITH_X265: 1, WITH_AOM: 1, WITH_LIBDE265: 3, GCC: 13 }
           - { NAME: "gcc-14", WITH_GRAPHICS: 1, WITH_X265: 1, WITH_AOM: 1, WITH_LIBDE265: 3, GCC: 14 }
+          - { NAME: "gcc-15", WITH_GRAPHICS: 1, WITH_X265: 1, WITH_AOM: 1, WITH_LIBDE265: 3, GCC: 15 }
     env: ${{ matrix.env }}
     runs-on: ubuntu-24.04
     steps:
@@ -22,6 +23,10 @@ jobs:
     - name: Install dependencies
       run: |
         ./scripts/install-ci-linux.sh
+        # gcc-15 is not in the noble main archives yet; pull it from the
+        # ubuntu-toolchain-r/test PPA. The line is harmless for older GCCs.
+        sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+        sudo apt update
         sudo apt install gcc-${GCC} g++-${GCC}

     - name: Prepare CI