--- SConstruct.orig	2020-12-03 12:39:40.759793977 -0600
+++ gpsd-3.21/SConstruct	2020-12-03 12:44:30.858761753 -0600
@@ -516,9 +516,11 @@
     'CWRAPPERS_CONFIG_DIR',      # pkgsrc
     # Variables used in testing
     'WRITE_PAD',       # So we can test WRITE_PAD values on the fly.
+    'LD_LIBRARY_PATH', # Allows running 'scons check' without 'chrpath'
+    'XML_CATALOG_FILES', # Enables validating the manual with 'xmlto' using nix build system
 )
 
-envs = {}
+envs = os.environ
 for var in import_env:
     if var in os.environ:
         envs[var] = os.environ[var]