[gnome-builder] build: allow libportal access to plugins

[Christian Hergert <chergert src gnome org>]

commit 9ca3737360f0de90445aa85ea00a359d8e5865ba
Author: Christian Hergert <chergert redhat com>
Date:   Sat Jun 27 14:06:49 2020 -0700

    build: allow libportal access to plugins
    
    Not currently required, but allows plugins to optionally use features from
    libportal to access desktop features.
    
    We probably need to figure out how we want to use these things and stay
    compatible with other platforms like macOS in the future.

 meson.build                            | 6 ++++++
 src/plugins/update-manager/meson.build | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 53320d109..d846457dc 100644
--- a/meson.build
+++ b/meson.build
@@ -261,6 +261,7 @@ libjsonrpc_glib_dep = dependency('jsonrpc-glib-1.0', version: '>= 3.29.91')
 libm_dep = cc.find_library('m', required: false)
 libpangoft2_dep = dependency('pangoft2', version: '>= 1.38.0')
 libpeas_dep = dependency('libpeas-1.0', version: '>= 1.22.0')
+libportal_dep = dependency('libportal', version: '>= 0.3', required: false)
 libtemplate_glib_dep = dependency('template-glib-1.0', version: '>= 3.28.0')
 libvte_dep = dependency('vte-2.91', version: '>= 0.40.2')
 libwebkit_dep = dependency('webkit2gtk-4.0', version: '>= 2.26')
@@ -287,6 +288,11 @@ if libsysprof_capture.found()
   config_h.set10('ENABLE_TRACING_SYSCAP', true)
 endif
 
+# Give sources access to know if libportal is available
+if libportal_dep.found()
+  config_h.set10('ENABLE_LIBPORTAL', true)
+endif
+
 configure_file(output: 'config.h', configuration: config_h)
 
 gnome = import('gnome')
diff --git a/src/plugins/update-manager/meson.build b/src/plugins/update-manager/meson.build
index 0cd402e3c..255d5af4c 100644
--- a/src/plugins/update-manager/meson.build
+++ b/src/plugins/update-manager/meson.build
@@ -1,7 +1,7 @@
 if get_option('plugin_update_manager')
 
 plugins_deps += [
-  dependency('libportal', version: '>= 0.3'),
+  libportal_dep,
 ]
 
 plugins_sources += files([