Fix build for x86_64 target

The added file is from the upstream QEMU (0.10.5), and the code is based on
the following commit:

    commit d2e9fd8f703203c2eeeed120b1ef6c3a6574e0ab
    Author: malc <av1474@comtv.ru>
    Date:   Sat Jun 20 05:51:47 2009 +0400

    Apply TCGV_UNUSED on variables that GCC mistakenly thinks can be used
    uninitialized

For: ABIT-15

Change-Id: I4f675784c1e8649e99d1bd0c76eced6a3df14680
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Jun Tian <jun.j.tian@intel.com>
diff --git a/Makefile.target b/Makefile.target
index 43e0d9c..45e3512 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -53,6 +53,7 @@
 
 common_LOCAL_SRC_FILES += \
     tcg/tcg.c \
+    tcg-runtime.c \
 
 ##############################################################################
 # Emulated hardware devices.