Need higher resolution times for linpack benchmark

[N.M. Maclaren]

This is nor a gfortran answer, but here is a wall-clock timer that is
callable from Fortran and I use when I need it.

/* Return high-precision timestamp. */
#include <stddef.h>
#include <sys/time.h>
double gettime_ (void) {
        struct timeval timer;
        if (gettimeofday(&timer,NULL))
                return -1.0;
        return timer.tv_sec+
                1.0e-6*timer.tv_usec;
}

Regards,
Nick Maclaren.