[libgweather/wip/hadess/fixes: 1/13] build: Use external file as a symbol export map

[Bastien Nocera <hadess src gnome org>]

commit f82ba4562dbe7b2c5b9ff76f9bab9ebd0b1a1072
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Jan 11 14:21:58 2021 +0100

    build: Use external file as a symbol export map
    
    Rather than relying on GWEATHER_EXTERN.

 libgweather/libgweather.map | 10 ++++++++++
 libgweather/meson.build     | 10 ++++++++++
 2 files changed, 20 insertions(+)
---
diff --git a/libgweather/libgweather.map b/libgweather/libgweather.map
new file mode 100644
index 00000000..0e89eac7
--- /dev/null
+++ b/libgweather/libgweather.map
@@ -0,0 +1,10 @@
+{
+  global:
+    gweather_*;
+    _gweather_location_reset_world;
+    _radians_to_degrees_str;
+
+  local:
+    *;
+};
+
diff --git a/libgweather/meson.build b/libgweather/meson.build
index 73372149..6a055a49 100644
--- a/libgweather/meson.build
+++ b/libgweather/meson.build
@@ -6,6 +6,14 @@ add_project_arguments([
 ], language: 'c')
 
 header_subdir = 'libgweather-3.0/libgweather'
+libgweather_map = join_paths(meson.current_source_dir(), 'libgweather.map')
+link_depends = []
+link_args = []
+
+if c_compiler.has_link_argument('-Wl,--version-script,' + libgweather_map)
+        link_depends += libgweather_map
+        link_args += ['-Wl,--version-script,' + libgweather_map]
+endif
 
 versionconf = configuration_data()
 versionconf.set('GWEATHER_MAJOR_VERSION', libgweather_version[0])
@@ -59,6 +67,8 @@ lib_libgweather = shared_library('gweather-3',
   gweather_c_sources,
   include_directories: root_inc,
   dependencies: deps_libgweather,
+  link_depends: link_depends,
+  link_args: link_args,
   version: libgweather_so_version,
   darwin_versions: libgweather_darwin_versions,
   install: true,