signbit          2578 src/heap.cc      ASSERT(signbit(minus_zero_value()->Number()) != 0);
signbit            64 src/platform-solaris.cc #ifndef signbit
signbit            48 src/platform.h # ifndef signbit
signbit            49 src/platform.h int signbit(double x);
signbit            59 src/win32-math.h int signbit(double x);