Fix compilation with locales disabled (#1011)

test/locale-test.cc

@@ -8,6 +8,7 @@
 #include "fmt/locale.h"
 #include "gmock.h"
 
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
 template <typename Char> struct numpunct : std::numpunct<Char> {
  protected:
   Char do_thousands_sep() const FMT_OVERRIDE { return '~'; }
@@ -31,3 +32,4 @@ TEST(LocaleTest, WFormat) {
   fmt::format_arg_store<fmt::wformat_context, int> as{1234567};
   EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:n}", fmt::wformat_args(as)));
 }
+#endif  // FMT_STATIC_THOUSANDS_SEPARATOR