[json-glib] build: Update the macOS linker flags

[Emmanuele Bassi <ebassi src gnome org>]

commit ec2525b4aad70379387a95142ad09b396c660f0b
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Jul 18 11:04:30 2017 +0100

    build: Update the macOS linker flags
    
    Use the interface and binary ages to define the current version.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785053

 meson.build |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index ff41fc7..5d33c64 100644
--- a/meson.build
+++ b/meson.build
@@ -147,7 +147,10 @@ endif
 
 # Maintain compatibility with autotools
 if host_system == 'darwin'
-  common_ldflags += [ '-compatibility_version 1', '-current_version 1.0', ]
+  common_ldflags += [
+    '-compatibility_version 1',
+    '-current_version @0@.@1@'.format(json_binary_age - json_interface_age, json_interface_age),
+  ]
 endif
 
 root_dir = include_directories('.')