linux-user: Add support for clock_adjtime() syscall

This patch implements Qemu user mode clock_adjtime() syscall support.

The implementation is based on invocation of host's clock_adjtime().

Signed-off-by: Aleksandar Rikalo <aleksandar.rikalo@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/configure b/configure
index dd9e679..1ce3d00 100755
--- a/configure
+++ b/configure
@@ -3911,6 +3911,21 @@
   setns=yes
 fi
 
+# clock_adjtime probe
+clock_adjtime=no
+cat > $TMPC <<EOF
+#include <time.h>
+
+int main(void)
+{
+    return clock_adjtime(0, 0);
+}
+EOF
+clock_adjtime=no
+if compile_prog "" "" ; then
+  clock_adjtime=yes
+fi
+
 # Check if tools are available to build documentation.
 if test "$docs" != "no" ; then
   if has makeinfo && has pod2man; then
@@ -5196,6 +5211,9 @@
 if test "$setns" = "yes" ; then
   echo "CONFIG_SETNS=y" >> $config_host_mak
 fi
+if test "$clock_adjtime" = "yes" ; then
+  echo "CONFIG_CLOCK_ADJTIME=y" >> $config_host_mak
+fi
 if test "$inotify" = "yes" ; then
   echo "CONFIG_INOTIFY=y" >> $config_host_mak
 fi