Emulation of `getloadavg' on MS-Windows:

Emulation of `getloadavg' on MS-Windows:
Include float.h
(g_b_init_get_native_system_info, g_b_init_get_system_times)
(GetNativeSystemInfo_Proc, GetSystemTimes_Proc): Declare.
(get_native_system_info, get_system_times): New functions.
(buf_next, buf_prev, sample_system_load, getavg): New subroutines.
(getloadavg): Rewrite using GetSystemTimes and GetNativeSystemInfo.
(globals_of_w32): Initialize g_b_init_get_native_system_info,
g_b_init_get_system_times, and num_of_processors.