[calls] Add libcall-ui as submodule

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit 8cb2c09f7bae85f85f62fd1a98e1fb945d7fffd7
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Fri Oct 1 18:34:56 2021 +0200

    Add libcall-ui as submodule
    
    This is meant to ease sharing the call ui between calls and phosh.

 .gitmodules            | 3 +++
 meson.build            | 4 ++++
 subprojects/libcall-ui | 1 +
 3 files changed, 8 insertions(+)
---
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 00000000..c72fa6c7
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "subprojects/libcall-ui"]
+       path = subprojects/libcall-ui
+       url = https://gitlab.gnome.org/World/Phosh/libcall-ui.git
diff --git a/meson.build b/meson.build
index 9c7d402c..16c0973d 100644
--- a/meson.build
+++ b/meson.build
@@ -48,6 +48,10 @@ full_calls_plugin_libdir = join_paths(prefix, libdir, calls_name, 'plugins')
 # Path to plugins inside the build dir, used for testing
 full_calls_plugin_builddir = join_paths(builddir, 'plugins')
 
+libcall_ui_dep = dependency('call-ui',
+  fallback:  ['libcall-ui', 'libcall_ui_dep'],
+)
+
 config_data = configuration_data()
 config_data.set_quoted('APP_ID', calls_id)
 config_data.set_quoted('APP_DATA_NAME', calls_name)
diff --git a/subprojects/libcall-ui b/subprojects/libcall-ui
new file mode 160000
index 00000000..6e2c2cc4
--- /dev/null
+++ b/subprojects/libcall-ui
@@ -0,0 +1 @@
+Subproject commit 6e2c2cc4cea11726ee2c0e7785932566db85ae17