build_library: Move and fix pkg_use_enabled into

There were two problems with pkg_use_enabled:

1. It did not detect force-enabled or masked USE flags correctly -
   selinux USE flag is force-enabled and is shown in the output inside
   parentheses.

2. It was defined in board_options.sh which injects some command line
   flags and globals that are not related to the function.

Since pkg_use_enabled was only used so far for checking the selinux
USE flags, add a function is_selinux_enabled and use the newly added
function in the currently only user of pkg_use_enabled.

Signed-off-by: Krzesimir Nowak <knowak@microsoft.com>

build_library/board_options.sh

@@ -14,23 +14,6 @@ ARCH=$(get_board_arch ${BOARD})
 # What cross-build are we targeting?
 . "${BOARD_ROOT}/etc/portage/make.conf" || die
 
-# check if any of the given use flags are enabled for a pkg
-pkg_use_enabled() {
-  local pkg="${1}"; shift
-
-  # for every flag argument, turn it into a regexp that matches it as
-  # either '+${flag}' or '(+${flag})'
-  local -a grep_args=()
-  local flag
-  for flag; do
-      grep_args+=( -e '^(\?+'"${flag}"')\?$' )
-  done
-  local -i rv=0
-
-  equery-"${BOARD}" --quiet uses --forced-masked "${pkg}" | grep --quiet "${grep_args[@]}" || rv=$?
-  return ${rv}
-}
-
 # Usage: pkg_version [installed|binary|ebuild] some-pkg/name
 # Prints: some-pkg/name-1.2.3
 # Note: returns 0 even if the package was not found.

build_library/build_image_util.sh

@@ -19,6 +19,7 @@ fi
 BUILD_DIR="${FLAGS_output_root}/${BOARD}/${IMAGE_SUBDIR}"
 OUTSIDE_OUTPUT_DIR="../build/images/${BOARD}/${IMAGE_SUBDIR}"
 
+source "${BUILD_LIBRARY_DIR}/pkg_util.sh" || exit 1
 source "${BUILD_LIBRARY_DIR}/reports_util.sh" || exit 1
 source "${BUILD_LIBRARY_DIR}/sbsign_util.sh" || exit 1
 
@@ -685,7 +686,7 @@ EOF
   fi
 
   # Build the selinux policy
-  if pkg_use_enabled coreos-base/coreos selinux; then
+  if is_selinux_enabled "${BOARD}"; then
     info "Building selinux mcs policy"
     sudo chroot "${root_fs_dir}" bash -s <<'EOF'
 cd /usr/share/selinux/mcs
@@ -725,7 +726,7 @@ EOF
   # SELinux: Label the root filesystem for using 'file_contexts'.
   # The labeling has to be done before moving /etc to /usr/share/flatcar/etc to prevent wrong labels for these files and as
   # the relabeling on boot would cause upcopies in the overlay.
-  if pkg_use_enabled coreos-base/coreos selinux; then
+  if is_selinux_enabled "${BOARD}"; then
     # -D - set or update any directory SHA1 digests
     # -E - treat conflicting specifications as errors
     # -F - force reset of context to match file_context

build_library/pkg_util.sh

@@ -0,0 +1,30 @@
+# Copyright (c) 2025 The Flatcar Maintainers. All rights reserved.
+# Use of this source code is governed by the Apache 2.0 license.
+
+# check if any of the given use flags are enabled for a pkg
+pkg_use_enabled() {
+  local board=${1}; shift
+  local pkg=${1}; shift
+
+  # for every flag argument, turn it into a regexp that matches it as
+  # either '+${flag}' or '(+${flag})'
+  local -a grep_args=()
+  local flag
+  for flag; do
+    grep_args+=( -e '^(\?+'"${flag}"')\?$' )
+  done
+  local -i rv=0
+  local equery='equery'
+  if [[ -n ${board} ]]; then
+    equery+="-${board}"
+  fi
+
+  "${equery}" --quiet uses --forced-masked "${pkg}" | grep --quiet "${grep_args[@]}" || rv=$?
+  return ${rv}
+}
+
+is_selinux_enabled() {
+  local board=${1}; shift
+
+  pkg_use_enabled "${board}" coreos-base/coreos selinux
+}