diff --git a/SCons/Config/ms b/SCons/Config/ms
index cce1da83..c35edca5 100644
--- a/SCons/Config/ms
+++ b/SCons/Config/ms
@@ -25,7 +25,8 @@ if defenv['DEBUG']:
 # if stl usage causes link failure, copy the good libcp.lib
 # from one of the other lib folders and use it instead.
 
-conf = defenv.Configure()
+confenv = defenv.Copy()
+conf = confenv.Configure()
 
 libcptest = """
 #include <fstream>
@@ -50,6 +51,7 @@ if not conf.TryLink(libcptest % 'no change', '.cpp'):
 			libcp = r'%s\libcp.lib' % libdir
 			shutil.copy(libcp, Dir('#/.sconf_temp').abspath)
 			if conf.TryLink(libcptest % (r'using %s' % libcp), '.cpp'):
+				defenv.PrependENVPath('LIB', Dir('#/.sconf_temp').abspath)
 				break
 		except IOError:
 			continue