Don't use arrays in the configure script

The configure script requires Bourne shell, but arrays are Bash
extension.

Change-Id: I60031e447e3c3c5a606e9ebaf3073a469fe08718
diff --git a/configure b/configure
index fc40c89..6c33f22 100755
--- a/configure
+++ b/configure
@@ -3804,23 +3804,20 @@
     if $pkg_config --atleast-version=$glib_req_ver $i; then
         glib_cflags=$($pkg_config --cflags $i)
         if test "$darwin" = "yes"; then
-          libdirs=()
-          glib_libs=()
           for l in $(pkg-config --static --libs $i); do
             case "${l}" in
-              -L*) libdirs+=("-B${l#-L}") ;;
+              -L*) libdirs="${libdirs:+${libdirs} }-B${l#-L}" ;;
               -l*)
-                lib="$($cc ${libdirs[@]} -print-file-name=lib${l#-l}.a)"
+                lib="$($cc ${libdirs} -print-file-name=lib${l#-l}.a)"
                 if [[ -f ${lib} ]]; then
-                  glib_libs+=("${lib}")
+                  glib_libs="${glib_libs:+${glib_libs} }${lib}"
                 else
-                 glib_libs+=("${l}")
+                 glib_libs="${glib_libs:+${glib_libs} }${l}"
                 fi
                 ;;
-              *) glib_libs+=("${l}")
+              *) glib_libs="${glib_libs:+${glib_libs} }${l}"
             esac
           done
-          glib_libs="${glib_libs[@]}"
         else
           glib_libs=$($pkg_config --libs $i)
         fi