Merge remote-tracking branch 'riku/linux-user-for-upstream' into staging

# By Peter Maydell (5) and others
# Via Riku Voipio
* riku/linux-user-for-upstream:
  linux-user/syscall.c: Don't warn about unimplemented get_robust_list
  linux-user: Implement accept4
  linux-user: Implement sendfile and sendfile64
  linux-user: make bogus negative iovec lengths fail EINVAL
  linux-user: Fix layout of usage table to account for option text
  linux-user: Add more sparc syscall numbers
  linux-user: Support setgroups syscall with no groups
  linux-user: fix futex strace of FUTEX_CLOCK_REALTIME
  linux-user/syscall.c: handle FUTEX_WAIT_BITSET in do_futex
  linux-user: improve print_fcntl()
  linux-user: Add Alpha socket constants

1 files changed, 17 insertions, 0 deletions

diff --git a/configure b/configure
index a382ff2562..46a75947cd 100755
--- a/configure
+++ b/configure
@@ -2764,6 +2764,20 @@ if compile_prog "" "" ; then
   epoll_pwait=yes
 fi
 
+# check for sendfile support
+sendfile=no
+cat > $TMPC << EOF
+#include <sys/sendfile.h>
+
+int main(void)
+{
+    return sendfile(0, 0, 0, 0);
+}
+EOF
+if compile_prog "" "" ; then
+  sendfile=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
   if has makeinfo && has pod2man; then
@@ -3633,6 +3647,9 @@ fi
 if test "$epoll_pwait" = "yes" ; then
   echo "CONFIG_EPOLL_PWAIT=y" >> $config_host_mak
 fi
+if test "$sendfile" = "yes" ; then
+  echo "CONFIG_SENDFILE=y" >> $config_host_mak
+fi
 if test "$inotify" = "yes" ; then
   echo "CONFIG_INOTIFY=y" >> $config_host_mak
 fi