.github: move qemu-user builds to separate pipeline

These builds just taking too long and slowing down all other builds.
Let's only run them on a few branches (eg. baselines) and not on
each single PR or arbitrary pushes.

It's only running on:

- master
- release/*
- qemu/*

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/workflows/build-qemu.yml

@@ -0,0 +1,84 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# Copyright (C) 2026 Enrico Weigelt, metux IT consult <info@metux.net>
+name: Build foreign architectures
+
+permissions:
+    contents: write
+
+env:
+    MESON_BUILDDIR:  "__BUILD"
+    X11_PREFIX:      /home/runner/x11
+    X11_BUILD_DIR:   /home/runner/work/xserver/xserver/WORK/sources/3rdparty
+    GOXPROTO_REF:    v0.0.8
+
+on:
+    push:
+        branches:
+            - master
+            - 'release/*'
+            - 'qemu/*'
+
+jobs:
+    xserver-build-qemu-user:
+        # Native (non-cross) build of the foreign CPU architectures referenced
+        # in include/compiler.h (__alpha__, __sparc__, __arm32__, __mips__,
+        # __powerpc__). Runs the real target-arch gcc under QEMU user-mode
+        # emulation (qemu-user-static + binfmt_misc + debootstrap), so the
+        # arch-specific inline-asm branches are genuinely compiled — the
+        # x86_64-host lanes never exercise them (the missing-" trailing ;" bugs
+        # in PR #3484/#3485 were invisible to every existing lane).
+        #
+        # ppc64el/armhf/mipsel are official Debian ports (bookworm); sparc64
+        # and alpha live in debian-ports (only unstable available).
+        runs-on: ubuntu-latest
+        timeout-minutes: 180
+        strategy:
+            fail-fast: false
+            matrix:
+                include:
+                    - name: ppc64el   # __powerpc__ (PowerPC64 little-endian)
+                      qemu: qemu-ppc64le-static
+                      suite: bookworm
+                      mirror: http://deb.debian.org/debian
+                    - name: armhf     # __arm32__ (ARM 32-bit)
+                      qemu: qemu-arm-static
+                      suite: bookworm
+                      mirror: http://deb.debian.org/debian
+                    - name: mipsel    # __mips__ (MIPS32 little-endian)
+                      qemu: qemu-mipsel-static
+                      suite: bookworm
+                      mirror: http://deb.debian.org/debian
+                    - name: sparc64   # __sparc__ (SPARC64)
+                      qemu: qemu-sparc64-static
+                      suite: unstable
+                      mirror: http://deb.debian.org/debian-ports
+                    - name: alpha     # __alpha__ (Alpha)
+                      qemu: qemu-alpha-static
+                      suite: unstable
+                      mirror: http://deb.debian.org/debian-ports
+        steps:
+            - uses: actions/checkout@v6
+
+            - name: QEMU cache key
+              id: cache-key
+              run: |
+                echo "key=qemu-rootfs-${{ matrix.name }}-${{ matrix.suite }}-${{ hashFiles('.github/scripts/qemu/run-qemu-build.sh') }}" >> $GITHUB_OUTPUT
+
+            - name: Restore QEMU rootfs cache
+              id: restore-cache
+              uses: actions/cache/restore@v4
+              with:
+                path: /tmp/qemu-rootfs-${{ matrix.name }}
+                key: ${{ steps.cache-key.outputs.key }}
+
+            - name: QEMU user-mode native build for ${{ matrix.name }}
+              run: sudo --preserve-env=MESON_ARGS,FDO_CI_CONCURRENT .github/scripts/qemu/run-qemu-build.sh ${{ matrix.name }} ${{ matrix.qemu }} ${{ matrix.suite }} ${{ matrix.mirror }}
+              env:
+                  MESON_ARGS: -Dprefix=/usr -Dwerror=true -Dxorg=true -Dxvfb=true -Dxnest=true -Dxephyr=true -Dxfbdev=false -Dglx=true -Dxcsecurity=true
+
+            - name: Save QEMU rootfs cache
+              if: always()
+              uses: actions/cache/save@v4
+              with:
+                path: /tmp/qemu-rootfs-${{ matrix.name }}
+                key: ${{ steps.cache-key.outputs.key }}

.github/workflows/build-xserver.yml

@@ -1011,70 +1011,6 @@ jobs:
                 path: |
                     ./.github/arch/xlibre-xserver-*.tar.zst
 
-    xserver-build-qemu-user:
-        # Native (non-cross) build of the foreign CPU architectures referenced
-        # in include/compiler.h (__alpha__, __sparc__, __arm32__, __mips__,
-        # __powerpc__). Runs the real target-arch gcc under QEMU user-mode
-        # emulation (qemu-user-static + binfmt_misc + debootstrap), so the
-        # arch-specific inline-asm branches are genuinely compiled — the
-        # x86_64-host lanes never exercise them (the missing-" trailing ;" bugs
-        # in PR #3484/#3485 were invisible to every existing lane).
-        #
-        # ppc64el/armhf/mipsel are official Debian ports (bookworm); sparc64
-        # and alpha live in debian-ports (only unstable available).
-        runs-on: ubuntu-latest
-        timeout-minutes: 180
-        strategy:
-            fail-fast: false
-            matrix:
-                include:
-                    - name: ppc64el   # __powerpc__ (PowerPC64 little-endian)
-                      qemu: qemu-ppc64le-static
-                      suite: bookworm
-                      mirror: http://deb.debian.org/debian
-                    - name: armhf     # __arm32__ (ARM 32-bit)
-                      qemu: qemu-arm-static
-                      suite: bookworm
-                      mirror: http://deb.debian.org/debian
-                    - name: mipsel    # __mips__ (MIPS32 little-endian)
-                      qemu: qemu-mipsel-static
-                      suite: bookworm
-                      mirror: http://deb.debian.org/debian
-                    - name: sparc64   # __sparc__ (SPARC64)
-                      qemu: qemu-sparc64-static
-                      suite: unstable
-                      mirror: http://deb.debian.org/debian-ports
-                    - name: alpha     # __alpha__ (Alpha)
-                      qemu: qemu-alpha-static
-                      suite: unstable
-                      mirror: http://deb.debian.org/debian-ports
-        steps:
-            - uses: actions/checkout@v6
-
-            - name: QEMU cache key
-              id: cache-key
-              run: |
-                echo "key=qemu-rootfs-${{ matrix.name }}-${{ matrix.suite }}-${{ hashFiles('.github/scripts/qemu/run-qemu-build.sh') }}" >> $GITHUB_OUTPUT
-
-            - name: Restore QEMU rootfs cache
-              id: restore-cache
-              uses: actions/cache/restore@v4
-              with:
-                path: /tmp/qemu-rootfs-${{ matrix.name }}
-                key: ${{ steps.cache-key.outputs.key }}
-
-            - name: QEMU user-mode native build for ${{ matrix.name }}
-              run: sudo --preserve-env=MESON_ARGS,FDO_CI_CONCURRENT .github/scripts/qemu/run-qemu-build.sh ${{ matrix.name }} ${{ matrix.qemu }} ${{ matrix.suite }} ${{ matrix.mirror }}
-              env:
-                  MESON_ARGS: -Dprefix=/usr -Dwerror=true -Dxorg=true -Dxvfb=true -Dxnest=true -Dxephyr=true -Dxfbdev=false -Dglx=true -Dxcsecurity=true
-
-            - name: Save QEMU rootfs cache
-              if: always()
-              uses: actions/cache/save@v4
-              with:
-                path: /tmp/qemu-rootfs-${{ matrix.name }}
-                key: ${{ steps.cache-key.outputs.key }}
-
     check-sign-off:
         name: Check Signed-Off-By
         if: github.event_name == 'pull_request'