--- lib/math.in.h.orig	2019-01-02 16:55:35.064459973 +0100
+++ lib/math.in.h	2019-01-02 17:42:43.450242836 +0100
@@ -2342,75 +2342,6 @@
 #endif
 
 
-#if @GNULIB_SIGNBIT@
-# if (@REPLACE_SIGNBIT_USING_GCC@ \
-      && (!defined __cplusplus || __cplusplus < 201103))
-#  undef signbit
-   /* GCC 4.0 and newer provides three built-ins for signbit.  */
-#  define signbit(x) \
-   (sizeof (x) == sizeof (long double) ? __builtin_signbitl (x) : \
-    sizeof (x) == sizeof (double) ? __builtin_signbit (x) : \
-    __builtin_signbitf (x))
-# endif
-# if @REPLACE_SIGNBIT@
-#  undef signbit
-_GL_EXTERN_C int gl_signbitf (float arg);
-_GL_EXTERN_C int gl_signbitd (double arg);
-_GL_EXTERN_C int gl_signbitl (long double arg);
-#  if __GNUC__ >= 2 && !defined __STRICT_ANSI__
-#   define _GL_NUM_UINT_WORDS(type) \
-      ((sizeof (type) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
-#   if defined FLT_SIGNBIT_WORD && defined FLT_SIGNBIT_BIT && !defined gl_signbitf
-#    define gl_signbitf_OPTIMIZED_MACRO
-#    define gl_signbitf(arg) \
-       ({ union { float _value;                                         \
-                  unsigned int _word[_GL_NUM_UINT_WORDS (float)];       \
-                } _m;                                                   \
-          _m._value = (arg);                                            \
-          (_m._word[FLT_SIGNBIT_WORD] >> FLT_SIGNBIT_BIT) & 1;          \
-        })
-#   endif
-#   if defined DBL_SIGNBIT_WORD && defined DBL_SIGNBIT_BIT && !defined gl_signbitd
-#    define gl_signbitd_OPTIMIZED_MACRO
-#    define gl_signbitd(arg) \
-       ({ union { double _value;                                        \
-                  unsigned int _word[_GL_NUM_UINT_WORDS (double)];      \
-                } _m;                                                   \
-          _m._value = (arg);                                            \
-          (_m._word[DBL_SIGNBIT_WORD] >> DBL_SIGNBIT_BIT) & 1;          \
-        })
-#   endif
-#   if defined LDBL_SIGNBIT_WORD && defined LDBL_SIGNBIT_BIT && !defined gl_signbitl
-#    define gl_signbitl_OPTIMIZED_MACRO
-#    define gl_signbitl(arg) \
-       ({ union { long double _value;                                   \
-                  unsigned int _word[_GL_NUM_UINT_WORDS (long double)]; \
-                } _m;                                                   \
-          _m._value = (arg);                                            \
-          (_m._word[LDBL_SIGNBIT_WORD] >> LDBL_SIGNBIT_BIT) & 1;        \
-        })
-#   endif
-#  endif
-#  define signbit(x) \
-   (sizeof (x) == sizeof (long double) ? gl_signbitl (x) : \
-    sizeof (x) == sizeof (double) ? gl_signbitd (x) : \
-    gl_signbitf (x))
-# endif
-# ifdef __cplusplus
-#  if defined signbit || defined GNULIB_NAMESPACE
-_GL_MATH_CXX_REAL_FLOATING_DECL_1 (signbit)
-#   undef signbit
-_GL_MATH_CXX_REAL_FLOATING_DECL_2 (signbit)
-#  endif
-# endif
-#elif defined GNULIB_POSIXCHECK
-# if defined signbit
-_GL_WARN_REAL_FLOATING_DECL (signbit);
-#  undef signbit
-#  define signbit(x) _GL_WARN_REAL_FLOATING_IMPL (signbit, x)
-# endif
-#endif
-
 _GL_INLINE_HEADER_END
 
 #endif /* _@GUARD_PREFIX@_MATH_H */