Switch to Clang and libc++

Change-Id: Id425997af58967e49094ab593ed8f0b70c72bbbc
diff --git a/native/jni/Android.mk b/native/jni/Android.mk
index 9657b9d..afb32d1 100644
--- a/native/jni/Android.mk
+++ b/native/jni/Android.mk
@@ -29,7 +29,7 @@
 
 LOCAL_CFLAGS += -Werror -Wall -Wextra -Weffc++ -Wformat=2 -Wcast-qual -Wcast-align \
     -Wwrite-strings -Wfloat-equal -Wpointer-arith -Winit-self -Wredundant-decls \
-    -Woverloaded-virtual -Wstrict-null-sentinel -Wsign-promo -Wno-system-headers
+    -Woverloaded-virtual -Wsign-promo -Wno-system-headers
 
 # To suppress compiler warnings for unused variables/functions used for debug features etc.
 LOCAL_CFLAGS += -Wno-unused-parameter -Wno-unused-function
@@ -60,8 +60,9 @@
 LOCAL_MODULE := libjni_latinime_common_static
 LOCAL_MODULE_TAGS := optional
 
+LOCAL_CLANG := true
 LOCAL_SDK_VERSION := 14
-LOCAL_NDK_STL_VARIANT := gnustl_static
+LOCAL_NDK_STL_VARIANT := c++_static
 
 include $(BUILD_STATIC_LIBRARY)
 ######################################
@@ -83,8 +84,9 @@
 LOCAL_MODULE := libjni_latinime
 LOCAL_MODULE_TAGS := optional
 
+LOCAL_CLANG := true
 LOCAL_SDK_VERSION := 14
-LOCAL_NDK_STL_VARIANT := gnustl_static
+LOCAL_NDK_STL_VARIANT := c++_static
 LOCAL_LDFLAGS += -ldl
 
 include $(BUILD_SHARED_LIBRARY)