- don't hardcode libstdc++

Index: build/php.m4
--- build/php.m4.orig
+++ build/php.m4
@@ -761,7 +761,9 @@ AC_DEFUN([PHP_REQUIRE_CXX], [
 AS_VAR_IF([php_cxx_done],, [
   AC_PROG_CXX
   AC_PROG_CXXCPP
-  PHP_ADD_LIBRARY([stdc++])
+  for i in $LIBCXX; do
+    PHP_ADD_LIBRARY($i)
+  done
   php_cxx_done=yes
 ])
 ])
