--- SConstruct.orig	2013-03-22 20:55:25.000000000 +0100
+++ SConstruct	2013-03-26 20:22:38.000000000 +0100
@@ -702,7 +702,7 @@
     env.Append( LIBS=[] )
 
     #make scons colorgcc friendly
-    for key in ('HOME', 'TERM'):
+    for key in ('HOME', 'TERM', 'PATH', 'CCACHE_DIR'):
         try:
             env['ENV'][key] = os.environ[key]
         except KeyError:
@@ -805,6 +805,20 @@
             print( "c++ compiler not installed!" )
             Exit(1)
 
+    if use_system_version_of_library("pcre"):
+        if not conf.CheckLib("pcrecpp"):
+            Exit(1)
+        if not conf.CheckLib("pcre"):
+            Exit(1)
+
+    if use_system_version_of_library("snappy"):
+        if not conf.CheckLib("snappy"):
+            Exit(1)
+
+    if usesm and use_system_version_of_library("sm"):
+        if not conf.CheckLib("js"):
+            Exit(1)
+
     if use_system_version_of_library("boost"):
         if not conf.CheckCXXHeader( "boost/filesystem/operations.hpp" ):
             print( "can't find boost headers" )