From 2df419cdb5295b405a98d24f0226cb42bfbf37d2 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sat, 23 Sep 2023 00:15:46 -0700
Subject: New function: rlink.

This uses the linkat function to implement a variant of
link which resolves the source object if it is a symlink.

* configure: test for linkat.

* sysif.c (link_wrap_common): New static function, used
by both link_wrap and rlink_wrap.
(link_wrap): Now a one-liner which calls link_wrap_common.
(rlink_wrap): New static function.
(sysif_init): Register rlink intrinsic.

* txr.1: Documented.
---
 configure | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'configure')

diff --git a/configure b/configure
index 51f7723c..256abb72 100755
--- a/configure
+++ b/configure
@@ -2665,6 +2665,26 @@ else
   printf "no\n"
 fi
 
+printf "Checking for linkat ... "
+
+cat > conftest.c <<!
+#include <unistd.h>
+#include <fcntl.h>
+
+int main(void)
+{
+  int e1 = linkat(AT_FDCWD, "foo", AT_FDCWD, "bar", AT_SYMLINK_FOLLOW);
+  return 0;
+}
+!
+if conftest ; then
+  printf "yes\n"
+  printf "#define HAVE_LINKAT 1\n" >> config.h
+  have_unistd=y
+else
+  printf "no\n"
+fi
+
 printf "Checking for POSIX mkdir ... "
 
 cat > conftest.c <<!
-- 
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