ruby and --prefix

[alip]

Ruby bindings don't play nice with --prefix e.g. installing under $HOME The responsible code snippet from configure.ac looks like:

        AC_MSG_CHECKING([for Ruby sitearchdir])
        RUBY_SITEARCHDIR=`$RUBY -r rbconfig -e 'puts Config::CONFIG@<:@"sitearchdir"@:>@'`
        if test x"$RUBY_SITEARCHDIR" = x ; then
                AC_MSG_ERROR([Could not find Ruby sitearchdir])
        fi
        AC_MSG_RESULT([$RUBY_SITEARCHDIR])
        AC_SUBST([RUBY_SITEARCHDIR])

        AC_ARG_WITH([ruby-install-dir],
                AS_HELP_STRING([--with-ruby-install-dir=dir], [Specify Ruby installation dir]),
                RUBY_INSTALL_DIR=`eval echo $withval`,
                RUBY_INSTALL_DIR=)
        AC_MSG_CHECKING([for Ruby installation dir])
        if test x"$RUBY_INSTALL_DIR" = x ; then
                RUBY_INSTALL_DIR="$RUBY_SITEARCHDIR"
        fi
        AC_MSG_RESULT([$RUBY_INSTALL_DIR])
        AC_SUBST([RUBY_INSTALL_DIR])

$RUBY_SITEARCHDIR may not always be what the user wants.
A workaround is specifying --with-ruby-install-dir=