diff --git a/configure.in b/configure.in
index 6450784b71..453cd144e3 100644
--- a/configure.in
+++ b/configure.in
@@ -6978,15 +6978,6 @@ if test "x$INTELCXX" = "xyes" ; then
 elif test "$GXX" = yes ; then
     dnl CXXWARNINGS="-Wall -W -Wcast-qual -Werror"
     CXXWARNINGS="-Wall -Wundef -Wno-ctor-dtor-privacy" 
-
-    dnl -Wno-format is a terrifically useful warning, however mingw warns
-    dnl whenever the I64 format specifier is used for long long.
-    dnl FIXME: it we detected when cygwin is using -mno-cygwin we could avoid
-    dnl disabling it for cygwin.
-    case "${host}" in
-        *-*-cygwin* | *-*-mingw32* )
-            CXXWARNINGS="$CXXWARNINGS -Wno-format"
-    esac
 fi
 
 EXTRA_CFLAGS="$WXDEBUG $WXODBCFLAG $PROFILE $OPTIMISE"
diff --git a/include/wx/string.h b/include/wx/string.h
index 844cfa9f81..4cd3a70575 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -958,10 +958,16 @@ public:
 #if defined wxLongLong_t && !defined wxLongLongIsLong
       // insert a long long if they exist and aren't longs
   wxString& operator<<(wxLongLong_t ll)
-    { return (*this) << Format(_T("%") wxLongLongFmtSpec _T("d"), ll); }
+    {
+      const wxChar *fmt = _T("%") wxLongLongFmtSpec _T("d");
+      return (*this) << Format(fmt, ll);
+    }
       // insert an unsigned long long
   wxString& operator<<(wxULongLong_t ull)
-    { return (*this) << Format(_T("%") wxLongLongFmtSpec _T("u"), ull); }
+    {
+      const wxChar *fmt = _T("%") wxLongLongFmtSpec _T("u");
+      return (*this) << Format(fmt , ull);
+    }
 #endif
       // insert a float into string
   wxString& operator<<(float f)