--- a/SConstruct
+++ b/SConstruct
@@ -264,7 +264,7 @@ for i in ["AR", "ARFLAGS", "CCFLAGS", "C
             env.Replace(**{j: os.getenv(i)})
 for flag in ["LDFLAGS", "SHLINKFLAGS", "CPPFLAGS"]:
     if os.environ.has_key(flag):
-        env.MergeFlags({flag : [os.getenv(flag)]})
+        env.MergeFlags({flag : Split(os.getenv(flag))})
 
 
 # Keep scan-build options in the environment
