[glib-networking] Ensure giomoduledir is always set under prefix

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a76aaad33f1f12278dc8ec80e66fc41c744b7364
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Thu Mar 15 11:08:05 2018 -0500

    Ensure giomoduledir is always set under prefix
    
    We have to override the libdir defined in gio-2.0.pc, or we could wind
    up installing outside our install prefix.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=794358

 meson.build |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 130d517..1ea400d 100644
--- a/meson.build
+++ b/meson.build
@@ -46,7 +46,8 @@ endif
 glib_dep = dependency('glib-2.0', version: '>= 2.55.1')
 gio_dep = dependency('gio-2.0')
 
-gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir')
+gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir',
+                                                define_variable: ['libdir', libdir])
 assert(gio_module_dir != '', 'GIO_MODULE_DIR is missing from gio-2.0.pc')
 
 # *** Checks for LibProxy   ***