More const correctness.

Removed prototype for unimplemented getpgid() function.
Removed a value return from a void function.

lib/libc/other/stderr.c

@@ -2,12 +2,9 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-_PROTOTYPE( void std_err, (char *s));
-
-void std_err(s)
-char *s;
+void std_err(const char *s)
 {
-  register char *p = s;
+  register const char *p = s;
 
   while (*p != 0) p++;
   write(2, s, (int) (p - s));