signbit
#define signbit(x) __fp_type_select(x, __signbitf, __signbit, __signbitl)
#undef signbit
#define signbit(x) __extension__( \
#define signbit(x) __extension__( \
#undef signbit
#define signbit(x) __builtin_signbit(x)
#define signbit(x) (__builtin_signbit(x) != 0)
signbit(double d)
signbit(double d)
#define signbit %f50
#define signbit 0x78
#define signbit 0x20
#define signbit 0x78
#define signbit 0x78