Allow override of $STRIP to take effect when running the tests.

	* Makefile.am: Pass STRIP through to the testsuite.

Index: libtool/Makefile.am
===================================================================
--- libtool.orig/Makefile.am
+++ libtool/Makefile.am
@@ -466,6 +466,7 @@ TESTS_ENVIRONMENT = MAKE="$(MAKE)" CC="$
 	CPP="$(CPP)" CPPFLAGS="$(CPPFLAGS)" LD="$(LD)" LDFLAGS="$(LDFLAGS)" \
 	LIBS="$(LIBS)" LN_S="$(LN_S)" NM="$(NM)" RANLIB="$(RANLIB)" \
 	AR="$(AR)" AR_FLAGS="${AR_FLAGS}" AR_SEP="${AR_SEP}" \
+	STRIP="$(STRIP)" \
 	OBJEXT="$(OBJEXT)" EXEEXT="$(EXEEXT)" \
 	SHELL="$(SHELL)" CONFIG_SHELL="$(SHELL)" \
 	CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS)" CXXCPP="$(CXXCPP)" \