finished first version. but don't test.

system_bit.cmake

@@ -0,0 +1,28 @@
+IF(APPLE)
+    SET(HGL_BITS 64)
+ELSE()
+    IF(ANDROID)
+        if(ANDROID_ABI MATCHES ".*64.*")
+            SET(HGL_BITS 64)
+        else()
+            SET(HGL_BITS 32)
+        endif()
+    ELSE()
+        IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
+            SET(HGL_BITS 64)
+        ELSE()
+            SET(HGL_BITS 32)
+        ENDIF()
+    endif()
+endif()
+
+IF(HGL_BITS EQUAL 32)
+    add_definitions(-DHGL_32_BITS)
+    add_definitions(-DHGL_POINTER_UINT=uint32)
+ELSE()
+    add_definitions(-DHGL_64_BITS)
+    add_definitions(-DHGL_POINTER_UINT=uint64)
+ENDIF()
+
+Message("System is ${HGL_BITS} Bit")
+