[glib-networking] tls modules: Export load/unload/query symbols on MSVC

[Ignacio Casal Quinteiro <icq src gnome org>]

commit f68f3ff87315d949311e452e26d0154ddacb7a29
Author: Nirbheek Chauhan <nirbheek centricular com>
Date:   Wed Feb 20 14:47:04 2019 +0530

    tls modules: Export load/unload/query symbols on MSVC
    
    These must be explicitly exported or the DLLs outputted won't be
    loadable
    
    'g_io_gnutls_load': The specified procedure could not be found.
    Failed to load module: c:\path\to\lib\gio\modules\giognutls.dll
    
    The openssl module still needs the __declspec hack via extra_args
    because it uses the old g_io_module_load() API.
    
    See: https://gitlab.gnome.org/GNOME/glib-networking/merge_requests/22#note_441685

 tls/gnutls/gnutls-module.c | 6 +++---
 tls/gnutls/meson.build     | 1 -
 2 files changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/tls/gnutls/gnutls-module.c b/tls/gnutls/gnutls-module.c
index 8983bd7..8dd09ca 100644
--- a/tls/gnutls/gnutls-module.c
+++ b/tls/gnutls/gnutls-module.c
@@ -30,7 +30,7 @@
 #include "gtlsbackend-gnutls.h"
 
 
-void
+G_MODULE_EXPORT void
 g_io_gnutls_load (GIOModule *module)
 {
   gchar *locale_dir;
@@ -53,12 +53,12 @@ g_io_gnutls_load (GIOModule *module)
   g_free (locale_dir);
 }
 
-void
+G_MODULE_EXPORT void
 g_io_gnutls_unload (GIOModule *module)
 {
 }
 
-gchar **
+G_MODULE_EXPORT gchar **
 g_io_gnutls_query (void)
 {
   gchar *eps[] = {
diff --git a/tls/gnutls/meson.build b/tls/gnutls/meson.build
index c855544..4ff127e 100644
--- a/tls/gnutls/meson.build
+++ b/tls/gnutls/meson.build
@@ -31,7 +31,6 @@ module = shared_module(
   name_suffix: module_suffix,
   install: true,
   install_dir: gio_module_dir,
-  c_args: extra_args
 )
 
 if get_option('static_modules')