diff --git a/src/system/libroot/posix/glibc/math/complex.h b/src/system/libroot/posix/glibc/math/complex.h
index 7172cb6b63..c1f52b5900 100644
--- a/src/system/libroot/posix/glibc/math/complex.h
+++ b/src/system/libroot/posix/glibc/math/complex.h
@@ -27,13 +27,13 @@
 
 __BEGIN_DECLS
 
-#if __GNUC__ >= 7
-#define __isinfl(value) __builtin_isinfl(value)
+#if __GNUC__ >= 7 || defined(__clang__)
 #define __isnan(value) __builtin_isnan(value)
-#define __isnanf(value) __builtin_isnanf(value)
-#define __isnanl(value) __builtin_isnanl(value)
+#define __isnanf(value) __builtin_isnan(value)
+#define __isnanl(value) __builtin_isnan(value)
 #define __isinf(value) __builtin_isinf(value)
-#define __isinff(value) __builtin_isinff(value)
+#define __isinff(value) __builtin_isinf(value)
+#define __isinfl(value) __builtin_isinf(value)
 #endif
 
 /* We might need to add support for more compilers here.  But since ISO
diff --git a/src/system/libroot/posix/glibc/math/math_private.h b/src/system/libroot/posix/glibc/math/math_private.h
index 2c8f804d9b..6a75c49bfa 100644
--- a/src/system/libroot/posix/glibc/math/math_private.h
+++ b/src/system/libroot/posix/glibc/math/math_private.h
@@ -286,8 +286,6 @@ extern int   __kernel_rem_pio2l (long double*,long double*,int,int,
 /* prototypes required to compile the ldbl-96 support without warnings */
 extern int __finitel (long double);
 extern int __ilogbl (long double);
-extern int __isinfl (long double);
-extern int __isnanl (long double);
 extern long double __atanl (long double);
 extern long double __copysignl (long double, long double);
 extern long double __expm1l (long double);