randread: don't require -lrt

Programs like 'sort' were linking to -lrt in order to get
clock_gettime, but this was misguided: it wasted considerable
resources while gaining at most 10 bits of entropy.  Almost nobody
needs the entropy, and there are better ways to get much better
entropy for people who do need it.
* gl/lib/rand-isaac.c (isaac_seed): Include <sys/time.h> not
"gethrxtime.h".
(isaac_seed): Use gettimeofday rather than gethrxtime.
* gl/modules/randread (Depends-on): Depend on gettimeofday
and not gethrxtime.
* src/Makefile.am (mktemp_LDADD, shred_LDADD, shuf_LDADD, sort_LDADD):
(tac_LDADD): Omit $(LIB_GETHRXTIME); no longer needed.

1 files changed, 3 insertions, 3 deletions

diff --git a/gl/lib/rand-isaac.c b/gl/lib/rand-isaac.c
index 52d53a393..377caa605 100644
--- a/gl/lib/rand-isaac.c
+++ b/gl/lib/rand-isaac.c
@@ -35,10 +35,9 @@
 #include "rand-isaac.h"
 
 #include <string.h>
+#include <sys/time.h>
 #include <unistd.h>
 
-#include "gethrxtime.h"
-
 
 /* This index operation is more efficient on many processors */
 #define ind(mm, x) \
@@ -292,7 +291,8 @@ isaac_seed (struct isaac_state *s)
   { gid_t t = getgid ();   ISAAC_SEED (s, t); }
 
   {
-    xtime_t t = gethrxtime ();
+    struct timeval t;
+    gettimeofday (&t, NULL);
     ISAAC_SEED (s, t);
   }