Allow to build host gtest libraries in unbundled build.

You need to include external/libcxx and external/libcxxabi in the
unbundled branche's repo manifest, though.

Change-Id: I778f36ef941beb932ef28c02188b8c855435b051
(cherry-picked from commit e826aa4f99cf7d9e57fe9668e299a2808674ede4)
diff --git a/src/Android.mk b/src/Android.mk
index 7768e30..ec0a3c2 100644
--- a/src/Android.mk
+++ b/src/Android.mk
@@ -75,8 +75,6 @@
 
 include $(BUILD_STATIC_LIBRARY)
 
-# Don't build for unbundled branches
-ifeq (,$(TARGET_BUILD_APPS))
 #######################################################################
 # gtest lib host
 
@@ -108,6 +106,8 @@
 include $(BUILD_HOST_STATIC_LIBRARY)
 
 #######################################################################
+# Don't build for unbundled branches
+ifeq (,$(TARGET_BUILD_APPS))
 # gtest lib target
 
 include $(CLEAR_VARS)