meson: add install_tag to sd-boot, libsystemd and libudev

Allows to 'meson install --tags systemd-boot --no-rebuild' to install only the EFI
binaries, skipping the rest, for a very quick build:

$ ninja src/boot/efi/linuxx64.efi.stub
[21/21] Generating src/boot/efi/linuxx64.efi.stub with a custom command
$ ninja src/boot/efi/systemd-bootx64.efi
[10/10] Generating src/boot/efi/systemd-bootx64.efi with a custom command
$ DESTDIR=/tmp/foo meson install --tags systemd-boot --no-rebuild
Installing src/boot/efi/systemd-bootx64.efi to /tmp/foo/usr/lib/systemd/boot/efi

Requires Meson 0.60 to be used, prints a warning for unknown keyword
in earlier versions, but there's no failure

https://mesonbuild.com/Installing.html#installation-tags

2 files changed, 17 insertions, 5 deletions

diff --git a/.github/workflows/build_test.sh b/.github/workflows/build_test.sh
index 0c77be2a13..aa8fa97f4e 100755
--- a/.github/workflows/build_test.sh
+++ b/.github/workflows/build_test.sh
@@ -123,9 +123,13 @@ for args in "${ARGS[@]}"; do
     #   src/boot/efi/meson.build:52:16: ERROR: Fatal warnings enabled, aborting
     # when LINKER is set to lld so let's just not turn meson warnings into errors with lld
     # to make sure that the build systemd can pick up the correct efi-ld linker automatically.
-    if [[ "$LINKER" != lld ]]; then
-        additional_meson_args="--fatal-meson-warnings"
-    fi
+    # We use some features (like install_tag) that were introduced in 0.60, but that don't
+    # break running with older versions
+    # FIXME: re-enable once the minimum version is bumped to 0.60
+    #if [[ "$LINKER" != lld ]]; then
+    #    additional_meson_args="--fatal-meson-warnings"
+    #fi
+    additional_meson_args=""
     info "Checking build with $args"
     # shellcheck disable=SC2086
     if ! AR="$AR" \
diff --git a/.github/workflows/unit_tests.sh b/.github/workflows/unit_tests.sh
index ca7309b141..f689f97e40 100755
--- a/.github/workflows/unit_tests.sh
+++ b/.github/workflows/unit_tests.sh
@@ -60,7 +60,11 @@ for phase in "${PHASES[@]}"; do
                 # The docs build is slow and is not affected by compiler/flags, so do it just once
                 MESON_ARGS+=(-Dman=true)
             fi
-            run_meson --fatal-meson-warnings -Dnobody-group=nogroup --werror -Dtests=unsafe -Dslow-tests=true -Dfuzz-tests=true "${MESON_ARGS[@]}" build
+            # We use some features (like install_tag) that were introduced in 0.60, but that don't
+            # break running with older versions
+            # FIXME: re-enable once the minimum version is bumped to 0.60
+            # MESON_ARGS+=(--fatal-meson-warnings)
+            run_meson -Dnobody-group=nogroup --werror -Dtests=unsafe -Dslow-tests=true -Dfuzz-tests=true "${MESON_ARGS[@]}" build
             ninja -C build -v
             meson test -C build --print-errorlogs
             ;;
@@ -79,7 +83,11 @@ for phase in "${PHASES[@]}"; do
                     MESON_ARGS+=(-Dskip-deps=true)
                 fi
             fi
-            run_meson --fatal-meson-warnings -Dnobody-group=nogroup --werror -Dtests=unsafe -Db_sanitize=address,undefined "${MESON_ARGS[@]}" build
+            # We use some features (like install_tag) that were introduced in 0.60, but that don't
+            # break running with older versions
+            # FIXME: re-enable once the minimum version is bumped to 0.60
+            # MESON_ARGS+=(--fatal-meson-warnings)
+            run_meson -Dnobody-group=nogroup --werror -Dtests=unsafe -Db_sanitize=address,undefined "${MESON_ARGS[@]}" build
             ninja -C build -v
 
             export ASAN_OPTIONS=strict_string_checks=1:detect_stack_use_after_return=1:check_initialization_order=1:strict_init_order=1