- adds several config-options to allow for turning off certain features

  like
  o UCLIBC_HAS_GNU_ERROR
  o UCLIBC_HAS_BSD_ERR
  o UCLIBC_HAS_PTY
  o UCLIBC_HAS_GETPT (1)
  o UCLIBC_SYSCALL_STUBS
  o UCLIBC_SYSCALL_STUB_WARNING
  o UCLIBC_LINUX_SPECIFIC (2)
  o UCLIBC_BSD_SPECIFIC (3)
  o UCLIBC_NTP_LEGACY (4)
  o UCLIBC_SV4_DEPRECATED (5)
  o UCLIBC_HAVE_REALTIME (6)
  o UCLIBC_HAVE_ADVANCED_REALTIME (7)
  o UCLIBC_HAVE_EPOLL (8)
  o UCLIBC_HAVE_XATTR (9)
  o UCLIBC_HAVE_PROFILING (10)

(1) make non-standard getpt optional and implement standard posix_openpt
(2) fstatfs(), inotify_*(), ioperm(), iopl(), madvise(), modify_ldt(),
    personality()
    ppoll(), setresuid()
(3) mincore(), getdomainname(), setdomainname()
(4) ntp_adjtime(), ntp_gettime() aliases
(5) ustat() [use statfs(2) in your code instead]
(6) All marked as "(REALTIME)" in SUSv3
(7) All marked as "(ADVANCED REALTIME)" in SUSv3
(8) epoll_create(), epoll_ctl(), epoll_wait()
(9) all Extended Attributes
(10) helpers for gcc's -finstrument-functions

- Fixes _dl_exit()
- Implements sleep(3) for !UCLIBC_HAVE_REALTIME
- Implements usleep(3) for !UCLIBC_HAVE_REALTIME
- adds #warning about incorrect posix_fadvise{,64}()
- removes unused and unwanted uselib()

Net outcome is that an allnoconfig with HAVE_SHARED is now about 88k instead 
of formerly 130k.

2 files changed, 71 insertions, 4 deletions

diff --git a/libc/signal/Makefile.in b/libc/signal/Makefile.in
index 8429d2ef6..4451d6622 100644
--- a/libc/signal/Makefile.in
+++ b/libc/signal/Makefile.in
@@ -6,10 +6,15 @@
 #
 
 CSRC :=	allocrtsig.c killpg.c raise.c sigaction.c sigaddset.c sigandset.c \
-	sigblock.c sigdelset.c sigempty.c sigfillset.c siggetmask.c sighold.c \
-	sigignore.c sigintr.c sigisempty.c sigismem.c sigjmp.c signal.c \
-	sigorset.c sigpause.c sigrelse.c sigset.c sigsetmask.c sigsetops.c \
-	sysv_signal.c sigwait.c
+	sigblock.c sigdelset.c sigempty.c sigfillset.c siggetmask.c \
+	sigintr.c sigisempty.c sigismem.c sigjmp.c signal.c \
+	sigorset.c sigpause.c sigsetmask.c sigsetops.c sigwait.c
+ifeq ($(UCLIBC_HAS_OBSOLETE_BSD_SIGNAL),y)
+CSRC += sighold.c sigignore.c sigrelse.c sigset.c
+endif
+ifeq ($(UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL),y)
+CSRC += sysv_signal.c
+endif
 
 ifneq ($(strip $(ARCH_OBJS)),)
 CSRC := $(filter-out $(notdir $(ARCH_OBJS:.o=.c)),$(CSRC))
diff --git a/libc/signal/sigwait.c b/libc/signal/sigwait.c
index 8ff2541a0..99832f809 100644
--- a/libc/signal/sigwait.c
+++ b/libc/signal/sigwait.c
@@ -22,6 +22,7 @@
 #include <signal.h>
 #include <string.h>
 
+#if defined __UCLIBC_HAS_REALTIME__
 libc_hidden_proto(sigwaitinfo)
 
 int __sigwait (const sigset_t *set, int *sig) attribute_hidden;
@@ -34,6 +35,67 @@ int __sigwait (const sigset_t *set, int *sig)
 	}
 	return 1;
 }
+#else /* __UCLIBC_HAS_REALTIME__ */
+/* variant without REALTIME extensions */
+libc_hidden_proto(sigfillset)
+libc_hidden_proto(sigaction)
+libc_hidden_proto(sigsuspend)
+
+static int was_sig; /* obviously not thread-safe */
+static void ignore_signal(int sig)
+{
+	was_sig = sig;
+}
+int __sigwait (const sigset_t *set, int *sig) attribute_hidden;
+int __sigwait (const sigset_t *set, int *sig)
+{
+  sigset_t tmp_mask;
+  struct sigaction saved[NSIG];
+  struct sigaction action;
+  int save_errno;
+  int this;
+
+  /* Prepare set.  */
+  sigfillset (&tmp_mask);
+
+  /* Unblock all signals in the SET and register our nice handler.  */
+  action.sa_handler = ignore_signal;
+  action.sa_flags = 0;
+  sigfillset (&action.sa_mask);       /* Block all signals for handler.  */
+
+  /* Make sure we recognize error conditions by setting WAS_SIG to a
+     value which does not describe a legal signal number.  */
+  was_sig = -1;
+
+  for (this = 1; this < NSIG; ++this)
+    if (__sigismember (set, this))
+      {
+        /* Unblock this signal.  */
+        __sigdelset (&tmp_mask, this);
+
+        /* Register temporary action handler.  */
+        if (sigaction (this, &action, &saved[this]) != 0)
+          goto restore_handler;
+      }
+
+  /* Now we can wait for signals.  */
+  sigsuspend (&tmp_mask);
+
+ restore_handler:
+  save_errno = errno;
+
+  while (--this >= 1)
+    if (__sigismember (set, this))
+      /* We ignore errors here since we must restore all handlers.  */
+      sigaction (this, &saved[this], NULL);
+
+  __set_errno (save_errno);
+
+  /* Store the result and return.  */
+  *sig = was_sig;
+  return was_sig == -1 ? -1 : 0;
+}
+#endif /* __UCLIBC_HAS_REALTIME__ */
 libc_hidden_proto(sigwait)
 weak_alias(__sigwait,sigwait)
 libc_hidden_def(sigwait)