Merge from gnulib.

* src/conf_post.h (__has_builtin, assume): Remove; gnulib now does these.
* src/lisp.h: Include <verify.h>, for 'assume'.

This also incorpoprates:
2013-10-02 verify: new macro 'assume'
2013-09-26 dup2, dup3: work around another cygwin crasher
2013-09-26 getdtablesize: work around cygwin issue

5 files changed, 67 insertions, 8 deletions

diff --git a/lib/dup2.c b/lib/dup2.c
index 9219eb38238..f128e7a63cd 100644
--- a/lib/dup2.c
+++ b/lib/dup2.c
@@ -96,7 +96,11 @@ rpl_dup2 (int fd, int desired_fd)
   /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
      On Cygwin 1.5.x, dup2 (1, 1) returns 0.
      On Cygwin 1.7.17, dup2 (1, -1) dumps core.
+     On Cygwin 1.7.25, dup2 (1, 256) can dump core.
      On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC.  */
+#  if HAVE_SETDTABLESIZE
+  setdtablesize (desired_fd + 1);
+#  endif
   if (desired_fd < 0)
     fd = desired_fd;
   if (fd == desired_fd)
diff --git a/lib/getdtablesize.c b/lib/getdtablesize.c
index 9947405af61..355c17e3b9e 100644
--- a/lib/getdtablesize.c
+++ b/lib/getdtablesize.c
@@ -22,11 +22,11 @@
 
 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
 
-#include <stdio.h>
+# include <stdio.h>
 
-#include "msvc-inval.h"
+# include "msvc-inval.h"
 
-#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
 static int
 _setmaxstdio_nothrow (int newmax)
 {
@@ -44,10 +44,11 @@ _setmaxstdio_nothrow (int newmax)
 
   return result;
 }
-# define _setmaxstdio _setmaxstdio_nothrow
-#endif
+#  define _setmaxstdio _setmaxstdio_nothrow
+# endif
 
-/* Cache for the previous getdtablesize () result.  */
+/* Cache for the previous getdtablesize () result.  Safe to cache because
+   Windows also lacks setrlimit.  */
 static int dtablesize;
 
 int
@@ -83,4 +84,24 @@ getdtablesize (void)
   return dtablesize;
 }
 
+#elif HAVE_GETDTABLESIZE
+
+# include <sys/resource.h>
+# undef getdtablesize
+
+int
+rpl_getdtablesize(void)
+{
+  /* To date, this replacement is only compiled for Cygwin 1.7.25,
+     which auto-increased the RLIMIT_NOFILE soft limit until it
+     hits the compile-time constant hard limit of 3200.  Although
+     that version of cygwin supported a child process inheriting
+     a smaller soft limit, the smaller limit is not enforced, so
+     we might as well just report the hard limit.  */
+  struct rlimit lim;
+  if (!getrlimit (RLIMIT_NOFILE, &lim) && lim.rlim_max != RLIM_INFINITY)
+    return lim.rlim_max;
+  return getdtablesize ();
+}
+
 #endif
diff --git a/lib/gnulib.mk b/lib/gnulib.mk
index 32255181fb4..14d45e798e5 100644
--- a/lib/gnulib.mk
+++ b/lib/gnulib.mk
@@ -1707,6 +1707,7 @@ unistd.h: unistd.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''REPLACE_FTRUNCATE''@|$(REPLACE_FTRUNCATE)|g' \
 	      -e 's|@''REPLACE_GETCWD''@|$(REPLACE_GETCWD)|g' \
 	      -e 's|@''REPLACE_GETDOMAINNAME''@|$(REPLACE_GETDOMAINNAME)|g' \
+	      -e 's|@''REPLACE_GETDTABLESIZE''@|$(REPLACE_GETDTABLESIZE)|g' \
 	      -e 's|@''REPLACE_GETLOGIN_R''@|$(REPLACE_GETLOGIN_R)|g' \
 	      -e 's|@''REPLACE_GETGROUPS''@|$(REPLACE_GETGROUPS)|g' \
 	      -e 's|@''REPLACE_GETPAGESIZE''@|$(REPLACE_GETPAGESIZE)|g' \
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 874c628a63b..0e510d679c6 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -654,10 +654,19 @@ _GL_WARN_ON_USE (getdomainname, "getdomainname is unportable - "
 #if @GNULIB_GETDTABLESIZE@
 /* Return the maximum number of file descriptors in the current process.
    In POSIX, this is same as sysconf (_SC_OPEN_MAX).  */
-# if !@HAVE_GETDTABLESIZE@
+# if @REPLACE_GETDTABLESIZE@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef getdtablesize
+#   define getdtablesize rpl_getdtablesize
+#  endif
+_GL_FUNCDECL_RPL (getdtablesize, int, (void));
+_GL_CXXALIAS_RPL (getdtablesize, int, (void));
+# else
+#  if !@HAVE_GETDTABLESIZE@
 _GL_FUNCDECL_SYS (getdtablesize, int, (void));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (getdtablesize, int, (void));
+# endif
 _GL_CXXALIASWARN (getdtablesize);
 #elif defined GNULIB_POSIXCHECK
 # undef getdtablesize
diff --git a/lib/verify.h b/lib/verify.h
index d42d0750ee1..bf40b028c92 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -250,6 +250,30 @@ template <int w>
 
 #define verify(R) _GL_VERIFY (R, "verify (" #R ")")
 
+#ifndef __has_builtin
+# define __has_builtin(x) 0
+#endif
+
+/* Assume that R always holds.  This lets the compiler optimize
+   accordingly.  R should not have side-effects; it may or may not be
+   evaluated.  Behavior is undefined if R is false.  */
+
+#if (__has_builtin (__builtin_unreachable) \
+     || 4 < __GNUC__ + (5 <= __GNUC_MINOR__))
+# define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
+#elif 1200 <= _MSC_VER
+# define assume(R) __assume (R)
+#elif (defined lint \
+       && (__has_builtin (__builtin_trap) \
+           || 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__))))
+  /* Doing it this way helps various packages when configured with
+     --enable-gcc-warnings, which compiles with -Dlint.  It's nicer
+     when 'assume' silences warnings even with older GCCs.  */
+# define assume(R) ((R) ? (void) 0 : __builtin_trap ())
+#else
+# define assume(R) ((void) (0 && (R)))
+#endif
+
 /* @assert.h omit end@  */
 
 #endif