Fix kross Ruby FTBFS

(cherry picked from commit 79d643fc1e)

lib/kross/configure.in.in

@@ -66,6 +66,7 @@ if test "x$compile_kross" = "xyes" ; then
         RUBY_LIBDIR=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"libdir"@:>@)'`
         RUBY_INCLUDEDIR=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"rubyhdrdir"@:>@)'`
         RUBY_LIBRUBYARG=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"LIBRUBYARG_SHARED"@:>@)'`
+        RUBY_ENABLESHARED=yes
         AC_DEFINE_UNQUOTED(HAVE_RUBY_1_9, 1, [Defines if your system has Ruby 1.9.x])
       fi
     fi
@@ -77,6 +78,7 @@ if test "x$compile_kross" = "xyes" ; then
       RUBY_LIBDIR=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"libdir"@:>@)'`
       RUBY_INCLUDEDIR=$RUBY_ARCHDIR
       RUBY_LIBRUBYARG=`$RUBY -r rbconfig -e 'printf("%s",Config::CONFIG@<:@"LIBRUBYARG_SHARED"@:>@)'`
+      RUBY_ENABLESHARED=yes
     fi
     AC_MSG_RESULT([
                     archdir $RUBY_ARCHDIR,
@@ -94,6 +96,7 @@ if test "x$compile_kross" = "xyes" ; then
     AC_SUBST(RUBY_LIBRUBYARG)
     AC_SUBST(RUBY_SITEDIR)
     AC_SUBST(RUBY_CFLAGS)
+    AC_SUBST(RUBY_ENABLESHARED)
 
     AC_MSG_CHECKING(for Ruby header)