Added TARGET_IS_64_BIT flag for x86_64 and aarch64

Change-Id: Ibdf9dafa3aeaf4b58b4a559ed05e36e2793bf6ed
Signed-off-by: Alexey Volkov <alexey.v.volkov@intel.com>
diff --git a/core/combo/TARGET_linux-aarch64.mk b/core/combo/TARGET_linux-aarch64.mk
index 49cf9c0..bdb3017 100644
--- a/core/combo/TARGET_linux-aarch64.mk
+++ b/core/combo/TARGET_linux-aarch64.mk
@@ -40,6 +40,8 @@
 TARGET_GCC_VERSION := $(TARGET_GCC_VERSION_EXP)
 endif
 
+TARGET_IS_64_BIT := true
+
 TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_ARCH)/$(TARGET_ARCH_VARIANT).mk
 ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),)
 $(error Unknown ARM architecture version: $(TARGET_ARCH_VARIANT))