diff --git a/src/support/lyxsum.C b/src/support/lyxsum.C
index 22ddf19d51..c5c88a5c5a 100644
--- a/src/support/lyxsum.C
+++ b/src/support/lyxsum.C
@@ -18,6 +18,9 @@
 
 using std::endl;
 
+using std::string;
+
+
 // OK, this is ugly, but it is the only workaround I found to compile
 // with gcc (any version) on a system which uses a non-GNU toolchain.
 // The problem is that gcc uses a weak symbol for a particular
@@ -42,9 +45,6 @@ template class boost::detail::crc_table_t<32, 0x04C11DB7, true>;
 #include <sys/mman.h>
 
 
-using std::string;
-
-
 unsigned long lyx::support::sum(string const & file)
 {
 	lyxerr[Debug::FILES] << "lyx::sum() using mmap (lightning fast)"
diff --git a/src/support/os_win32.C b/src/support/os_win32.C
index 6b57494699..37dc599947 100644
--- a/src/support/os_win32.C
+++ b/src/support/os_win32.C
@@ -23,6 +23,7 @@
 
 using namespace lyx::support;
 using std::endl;
+using std::string;
 
 
 namespace {