diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9177f044fca..c02f9bf418a 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-19  Jonathan Wakely  <jwakely@redhat.com>
+
+	* testsuite/decimal/conversion-to-integral.cc: Use predefined macro
+	instead of non-standard glibc one.
+
 2017-10-16  François Dumont  <fdumont@gcc.gnu.org>
 
 	PR libstdc++/82558
diff --git a/libstdc++-v3/testsuite/decimal/conversion-to-integral.cc b/libstdc++-v3/testsuite/decimal/conversion-to-integral.cc
index 6fd59a67b70..cc48fa8729d 100644
--- a/libstdc++-v3/testsuite/decimal/conversion-to-integral.cc
+++ b/libstdc++-v3/testsuite/decimal/conversion-to-integral.cc
@@ -64,7 +64,7 @@ void
 conversion_to_integral_128 (void)
 {
   #undef MAXVAL
-  #define MAXVAL LONG_LONG_MAX
+  #define MAXVAL __LONG_LONG_MAX__
   decimal128 a, b (1), c (-1), d (MAXVAL), e (-MAXVAL);
   long long ll;