optimize signal mask ops. comment out "impossible" errors

    text           data     bss     dec     hex filename
-   1179             13       2    1194     4aa libc/misc/syslog/syslog.o
+   1165             13       2    1180     49c libc/misc/syslog/syslog.o
-    435              4       0     439     1b7 libc/pwd_grp/lckpwdf.o
+    393              4       0     397     18d libc/pwd_grp/lckpwdf.o
-     38              0       0      38      26 libc/signal/sigandset.o
+     32              0       0      32      20 libc/signal/sigandset.o
-     63              0       0      63      3f libc/signal/sigblock.o
+     56              0       0      56      38 libc/signal/sigblock.o
-     22              0       0      22      16 libc/signal/sigempty.o
+     20              0       0      20      14 libc/signal/sigempty.o
-     25              0       0      25      19 libc/signal/sigfillset.o
+     20              0       0      20      14 libc/signal/sigfillset.o
-     34              0       0      34      22 libc/signal/sigisempty.o
+     16              0       0      16      10 libc/signal/sigisempty.o
-     38              0       0      38      26 libc/signal/sigorset.o
+     32              0       0      32      20 libc/signal/sigorset.o
-    119              0       0     119      77 libc/signal/sigpause.o
+    113              0       0     113      71 libc/signal/sigpause.o
-    215              0       0     215      d7 libc/signal/sigset.o
+    211              0       0     211      d3 libc/signal/sigset.o
-     63              0       0      63      3f libc/signal/sigsetmask.o
+     56              0       0      56      38 libc/signal/sigsetmask.o
-    194              0       1     195      c3 libc/stdlib/abort.o
+    183              0       1     184      b8 libc/stdlib/abort.o
-    323              0       0     323     143 libc/unistd/sleep.o
+    309              0       0     309     135 libc/unistd/sleep.o

1 files changed, 3 insertions, 1 deletions

diff --git a/libc/signal/sigempty.c b/libc/signal/sigempty.c
index 96260fb92..56b62bc65 100644
--- a/libc/signal/sigempty.c
+++ b/libc/signal/sigempty.c
@@ -26,13 +26,15 @@
 /* libc_hidden_proto(sigemptyset) */
 int sigemptyset (sigset_t *set)
 {
+#if 0 /* is it really required by standards?! */
   if (set == NULL)
     {
       __set_errno (EINVAL);
       return -1;
     }
+#endif
 
-  memset (set, 0, sizeof (sigset_t));
+  __sigemptyset (set);
 
   return 0;
 }