patch 8.2.2586: process id may be invalid

Problem:    Process id may be invalid.
Solution:   Use sysinfo.uptime to check for recent reboot. (suggested by Hugo
            van der Sanden, closes #7947)
diff --git a/src/auto/configure b/src/auto/configure
index 8183499..a9e2145 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -13918,6 +13918,35 @@
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for sysinfo.uptime" >&5
+$as_echo_n "checking for sysinfo.uptime... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+#include <sys/sysinfo.h>
+int
+main ()
+{
+	struct sysinfo sinfo;
+        long ut;
+
+	(void)sysinfo(&sinfo);
+	ut = sinfo.uptime;
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }; $as_echo "#define HAVE_SYSINFO_UPTIME 1" >>confdefs.h
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for sysconf" >&5
 $as_echo_n "checking for sysconf... " >&6; }
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext