Add array variable support to ossbuild-project-var-set/get

Use the new functionality for new project specific array variables:
- CONFIGURE_VARS: elements of the form NAME=VALUE will be set as
  environment variables when running autoconfig configure.
- CONFIGURE_OPTS: elements will be added to the options passed to
  autoconfig configure.

lib/ossbuild-common.bash

@@ -22,6 +22,11 @@ is-dry-run() {
     ! [ ${DRY_RUN:-0} -eq 0 ]
 }
 
+#D# Check if variable is an array.
+ossbuild-var-array-p() {
+    declare -p "${1}" 2> /dev/null | grep -Eq -- '^declare -a'
+}
+
 #D# Wrapper around pushd.
 #
 # The wrapper provides the following features:
@@ -116,8 +121,8 @@ ossbuild-project-var-get() {
     }
     name="${positional[0]}"
 
-    unset default
-    [ "${#positional[*]}" -le 1 ] || local default="${positional[1]}"
+    local default
+    [ "${#positional[*]}" -le 1 ] || default="${positional[1]}"
 
     vname="$(ossbuild-project-var "${name}")"
     #echo "2/ossbuild-project-var-get: ${vname}${default:+, default=${default}}" >&2
@@ -131,12 +136,22 @@ ossbuild-project-var-get() {
         fi
     }
     #echo "R/ossbuild-project-var-get: ${vname}='${!vname}'" >&2
+    local -n pvar_ref="${vname}"
     if [ -v outvar ]; then
         local -n ovar_ref="${outvar}"
-        # shellcheck disable=SC2034
-        printf -v ovar_ref '%s' "${!vname}"
+        if ossbuild-var-array-p "${vname}"; then
+            ovar_ref=("${pvar_ref[@]}")
         else
-        printf '%s' "${!vname}"
+            ovar_ref="${pvar_ref}"
+        fi
+    else
+        if ossbuild-var-array-p "${vname}"; then
+            for v in "${pvar_ref[@]}"; do
+                printf '%s\n' "${v}"
+            done
+        else
+            printf '%s' "${pvar_ref}"
+        fi
     fi
 }
 
@@ -151,10 +166,51 @@ ossbuild-project-var-get() {
 #
 #     stdout (str): na
 ossbuild-project-var-set() {
-    local name="${1}" value="${2}" vname
+    #echo "1/ossbuild-project-var-set: ${@}" >&2
+    local quiet=0 array=0 name vname
+    local -a positional
+    while [ ${#} -gt 0 ]; do
+        case "${1}" in
+            -q | --quiet)
+                ((++quiet))
+                ;;
+            -a)
+                array=1
+                ;;
+            -*)
+                # ignore unknown option
+                ;;
+            *)
+                positional+=("${1}")
+                ;;
+        esac
+        shift
+    done
+
+    [ "${#positional[*]}" -gt 0 ] || {
+        bsl_logfe "missing project variable name"
+        return 10
+    }
+    name="${positional[0]}"
     vname="$(ossbuild-project-var "${name}")"
-    bsl_logi "set project variable: ${vname}='${value}'"
+    unset positional[0]
+    set "${positional[@]}"
+    [ "${#positional[@]}" -le 1 ] || array=1
+
+    unset "${vname}" # make sure that we start with a clean state
+    local msg='set project variable: '
+    if [ "${array}" -eq 0 ]; then
+        local value="${@}"
+        msg="${msg}${vname}=${value@Q}"
         declare -g "${vname}=${value}"
+    else
+        local value=("${@}")
+        msg="${msg}${vname}=(${value[*]@Q})"
+        declare -ga "${vname}"
+        declare -n pvar_ref="${vname}"
+        pvar_ref=("${value[@]}")
+    fi
+    [ "${quiet}" -gt 0 ] || bsl_logi "${msg}"
 }
 
 #D# Unset (delete) project specific variable.
@@ -507,12 +563,16 @@ ossbuild-autotools-build() {
         || configure_ok_p_fn='ossbuild-autotools-configure-ok-p'
     if ! "${configure_ok_p_fn}" "${build_tree}"; then
         bsl_logi "run configure ..."
-        local configure=(
+        local -a configure=(
             "${src_tree}/configure"
             --prefix="${PREFIX}"
-            "${configure_extra_opts[@]}"
         )
-        ossbuild-cmd "${configure[@]}"
+        local -a vars opts
+        ossbuild-project-var-get -q -v vars CONFIGURE_VARS || true
+        ossbuild-project-var-get -q -v opts CONFIGURE_OPTS || true
+        vars+=("PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig")
+        [ -n "${opts[*]}" ] || configure+=("${opts[@]}")
+        ossbuild-cmd env "${vars[@]}" "${configure[@]}"
     fi
     ossbuild-cmd make