Fix some win32 definitions

You can now use psapi.dll and pdh.dll. Some TODOs for Windows have been
cleared out. We might have a working load average for the platform that
should help GNU Make work well.

examples/loadavg.c

@@ -10,6 +10,7 @@
 #include "libc/calls/calls.h"
 #include "libc/log/check.h"
 #include "libc/stdio/stdio.h"
+#include "libc/time/time.h"
 
 int main(int argc, char *argv[]) {
   double x[3];