[gnome-calculator] GCalc: added subproject's variable for build dir

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 70cb5d5f9d3c62bda56eca05565e9b9a47d39eff
Author: Daniel Espinosa <esodan gmail com>
Date:   Thu Jun 13 08:14:53 2019 -0500

    GCalc: added subproject's variable for build dir
    
    This can be used by top project to find out VAPI, GIR or TYPELIB
    generated files.

 gcalc/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gcalc/meson.build b/gcalc/meson.build
index 66d1fb83..2073964e 100644
--- a/gcalc/meson.build
+++ b/gcalc/meson.build
@@ -119,6 +119,7 @@ sources = files([
 
 inc_libh = include_directories ('.')
 inc_libh_dep = declare_dependency (include_directories : inc_libh)
+gcalc_build_dir = meson.current_build_dir ()
 
 gcalc_deps = [
        gio,