[9fans] too many system calls.

[ron minnich]

Glibc /bin/date on Linux runs around 140 system calls. A quick pass
with ratrace shows that plan 9 /bin/date has 10.

The conclusion is clear: plan 9 date has way too much overhead. It's
1/14 the number of system calls of Glibc; why's it so big?

A quick pass on getpid() fixes the problem:

#include        <u.h>
#include        <libc.h>
#include        <tos.h>

int
getpid(void)
{
        return _tos->pid;
}

Now we're down to seven system calls. 1/20 of glibc. Much better! :-)

ron