diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 1888702d1994..04dfebf43ac9 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,9 @@
 2016-02-08  Jonathan Wakely  <jwakely@redhat.com>
 
+	* acinclude.m4 (GLIBCXX_CHECK_MATH11_PROTO): Remove accidentally
+	added 'constexpr' in previous commit.
+	* configure: Regenerate.
+
 	PR libstdc++/48891
 	* acinclude.m4 (GLIBCXX_CHECK_MATH11_PROTO): Enable isinf and isnan
 	checks for all targets except *-*-solaris2.* and ensure we find the
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index e667ccc741ba..95df24a9062d 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -2228,8 +2228,8 @@ AC_DEFUN([GLIBCXX_CHECK_MATH11_PROTO], [
              #undef isinf
              namespace std {
                using ::isinf;
-               constexpr bool isinf(float);
-               constexpr bool isinf(long double);
+               bool isinf(float);
+               bool isinf(long double);
              }
              using std::isinf;
              bool b = isinf(0.0);
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 02bb312be0dc..acbc6a6bd6e9 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -18284,8 +18284,8 @@ else
              #undef isinf
              namespace std {
                using ::isinf;
-               constexpr bool isinf(float);
-               constexpr bool isinf(long double);
+               bool isinf(float);
+               bool isinf(long double);
              }
              using std::isinf;
              bool b = isinf(0.0);