[glib-openssl] meson: fix the build

[Christoph Reiter <creiter src gnome org>]

commit 6de42e0b5ddc86dea62c2423108ce41cc242682b
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Mon May 21 19:04:13 2018 +0200

    meson: fix the build

 meson.build |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 7f09dec..d37b5ba 100644
--- a/meson.build
+++ b/meson.build
@@ -10,8 +10,8 @@ glib = dependency('glib-2.0', version: '>=' + glib_req)
 gobject = dependency('gobject-2.0', version: '>=' + glib_req)
 gio = dependency('gio-2.0', version: '>=' + glib_req)
 
-gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir',
-                                                define_variable: ['libdir', libdir])
+gio_module_dir = gio.get_pkgconfig_variable('giomoduledir',
+                                            define_variable: ['libdir', get_option('libdir')])
 assert(gio_module_dir != '', 'GIO_MODULE_DIR is missing from gio-2.0.pc')
 
 gio_querymodules = find_program('gio-querymodules')