Quash a whole bunch of warnings

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@145624 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/system_error b/include/system_error
index d65b29b..c9a8097 100644
--- a/include/system_error
+++ b/include/system_error
@@ -474,7 +474,7 @@
 operator<(const error_condition& __x, const error_condition& __y) _NOEXCEPT
 {
     return __x.category() < __y.category()
-        || __x.category() == __y.category() && __x.value() < __y.value();
+        || (__x.category() == __y.category() && __x.value() < __y.value());
 }
 
 // error_code
@@ -551,7 +551,7 @@
 operator<(const error_code& __x, const error_code& __y) _NOEXCEPT
 {
     return __x.category() < __y.category()
-        || __x.category() == __y.category() && __x.value() < __y.value();
+        || (__x.category() == __y.category() && __x.value() < __y.value());
 }
 
 inline _LIBCPP_INLINE_VISIBILITY