proposed patch to gpsd for versioning on darwin mac osx

it diff
diff --git a/SConstruct b/SConstruct
index 09c0825..34fcb6e 100644
--- a/SConstruct
+++ b/SConstruct
@@ -23,7 +23,7 @@

 # Release identification begins here
 gpsd_version = "3.1~dev"
-libgps_major = 20
+libgps_major = 22
 libgps_minor = 0
 libgps_age   = 0
 # Release identification ends here
@@ -581,6 +581,8 @@ def VersionedSharedLibrary(env, libname, libversion, lib_objs=[], parse_flags=[]
         ilib_suffix = '.' + libversion + shlib_suffix
         shlink_flags += [ '-current_version', '%s' % libversion,
                           '-undefined', 'dynamic_lookup' ]
+        shlink_flags += [ '-compatibility_version', '%s' % libversion,
+                          '-undefined', 'dynamic_lookup' ]

     ilib = env.SharedLibrary(libname,lib_objs,
                             SHLIBSUFFIX=ilib_suffix,