[glib-networking] Override prefix when computing giomodulesdir

[Michael Catanzaro <mcatanzaro src gnome org>]

commit ce11007edf3a3a723b34e872a924debb30be4d54
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Mon Apr 16 19:40:24 2018 -0500

    Override prefix when computing giomodulesdir
    
    This is slightly more robust, in case GLib goes crazy and decides to
    change the definition of giomodulesdir in the future.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 4c62023..1e68415 100644
--- a/meson.build
+++ b/meson.build
@@ -57,7 +57,7 @@ if glib_dep.type_name() == 'internal'
   gio_module_dir = glib_proj.get_variable('glib_giomodulesdir')
 else
   gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir',
-                                                  define_variable: ['libdir', libdir])
+                                                  define_variable: ['prefix', prefix])
 endif
 
 assert(gio_module_dir != '', 'GIO_MODULE_DIR is missing from gio-2.0.pc')