diff --git a/flang/lib/Evaluate/intrinsics-library.cpp b/flang/lib/Evaluate/intrinsics-library.cpp
index ce9dd6b7b3df8..977705acf7a9f 100644
--- a/flang/lib/Evaluate/intrinsics-library.cpp
+++ b/flang/lib/Evaluate/intrinsics-library.cpp
@@ -415,7 +415,7 @@ template <> struct HostRuntimeLibrary<double, LibraryVersion::LibmExtensions> {
   static_assert(map.Verify(), "map must be sorted");
 };
 
-#if HAS_FLOAT80 || HAS_LDBL128
+#if defined(__GLIBC__) && (HAS_FLOAT80 || HAS_LDBL128)
 template <>
 struct HostRuntimeLibrary<long double, LibraryVersion::LibmExtensions> {
   using F = FuncPointer<long double, long double>;
diff --git a/flang/runtime/Float128Math/math-entries.h b/flang/runtime/Float128Math/math-entries.h
index 151ed8a09fde0..47f1993f22d65 100644
--- a/flang/runtime/Float128Math/math-entries.h
+++ b/flang/runtime/Float128Math/math-entries.h
@@ -185,9 +185,6 @@ DEFINE_SIMPLE_ALIAS(Hypot, std::hypot)
 DEFINE_SIMPLE_ALIAS(Ilogb, std::ilogb)
 DEFINE_SIMPLE_ALIAS(Isinf, std::isinf)
 DEFINE_SIMPLE_ALIAS(Isnan, std::isnan)
-DEFINE_SIMPLE_ALIAS(J0, j0l)
-DEFINE_SIMPLE_ALIAS(J1, j1l)
-DEFINE_SIMPLE_ALIAS(Jn, jnl)
 DEFINE_SIMPLE_ALIAS(Ldexp, std::ldexp)
 DEFINE_SIMPLE_ALIAS(Lgamma, std::lgamma)
 DEFINE_SIMPLE_ALIAS(Llround, std::llround)
@@ -204,9 +201,15 @@ DEFINE_SIMPLE_ALIAS(Tan, std::tan)
 DEFINE_SIMPLE_ALIAS(Tanh, std::tanh)
 DEFINE_SIMPLE_ALIAS(Tgamma, std::tgamma)
 DEFINE_SIMPLE_ALIAS(Trunc, std::trunc)
+
+#if defined(__GLIBC__) && defined(_GNU_SOURCE)
+DEFINE_SIMPLE_ALIAS(J0, j0l)
+DEFINE_SIMPLE_ALIAS(J1, j1l)
+DEFINE_SIMPLE_ALIAS(Jn, jnl)
 DEFINE_SIMPLE_ALIAS(Y0, y0l)
 DEFINE_SIMPLE_ALIAS(Y1, y1l)
 DEFINE_SIMPLE_ALIAS(Yn, ynl)
+#endif
 
 // Use numeric_limits to produce infinity of the right type.
 #define F128_RT_INFINITY \