[glib] Meson: Add export-dynamic flag

[Xavier Claessens <xclaesse src gnome org>]

commit 487b1fd20c5e494366a82ddc0fa6b53b8bd779ad
Author: Xavier Claessens <xavier claessens collabora com>
Date:   Wed Jan 3 11:13:40 2018 -0500

    Meson: Add export-dynamic flag
    
    https://bugzilla.gnome.org/show_bug.cgi?id=788773

 gmodule/meson.build |  4 ++--
 meson.build         | 16 +++++++++++++++-
 2 files changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/gmodule/meson.build b/gmodule/meson.build
index ddec32ab0..8bb61897b 100644
--- a/gmodule/meson.build
+++ b/gmodule/meson.build
@@ -118,7 +118,7 @@ pkg.generate(libraries : [libgmodule, thread_dep],
   description : 'Dynamic module loader for GLib',
 )
 
-pkg.generate(libraries : [libgmodule],
+pkg.generate(libraries : [libgmodule, export_dynamic_ldflags],
   requires : ['glib-2.0'],
   version : glib_version,
   variables : [supported_var],
@@ -128,7 +128,7 @@ pkg.generate(libraries : [libgmodule],
   description : 'Dynamic module loader for GLib',
 )
 
-pkg.generate(libraries : [libgmodule],
+pkg.generate(libraries : [libgmodule, export_dynamic_ldflags],
   requires : ['glib-2.0'],
   version : glib_version,
   variables : [supported_var],
diff --git a/meson.build b/meson.build
index 31dc99f15..568ec6083 100644
--- a/meson.build
+++ b/meson.build
@@ -1770,7 +1770,21 @@ if libmount_dep.length() != 0
   glib_conf.set('HAVE_LIBMOUNT', 1)
 endif
 glib_conf.set('GIO_MODULE_DIR', glib_giomodulesdir)
-# FIXME: Missing: @G_MODULE_LDFLAGS@
+
+# Sadly Meson does not expose this value:
+# https://github.com/mesonbuild/meson/pull/3460
+if host_system == 'windows'
+  # Autotools explicitly removed --Wl,--export-all-symbols from windows builds,
+  # with no explanation. Do the same here for now but this could be revisited if
+  # if causes issues.
+  export_dynamic_ldflags = []
+elif host_system == 'cygwin'
+  export_dynamic_ldflags = ['-Wl,--export-all-symbols']
+elif host_system == 'darwin'
+  export_dynamic_ldflags = []
+else
+  export_dynamic_ldflags = ['-Wl,--export-dynamic']
+endif
 
 win32_cflags = []
 win32_ldflags = []