java - Custom SQLite using Android NDK, SQLite source code -

i'm developing app use new google maps (see google play services , libs) , gps localization. in app, have sqlite db composed single table called poi(double latitute,double longitude,varchar(45) poiname). @ every new gps value (latlng) need query db nearest poi. need use algorithm , wrote of similar in sql. not difficult. right?

the real problem is: sqlite doesn't have cos, sin , acos functions. tried follow answare using sqlite source code, android ndk, cygwin (i'm using w8) , project... togethers, reading official doc, no result.

is there good tutorial this? or can explain me step-by-step how that?

[edit: more info] created in project jni folder , put inside: sqlite source code; android.mk.

android.mk

#local_path used locate source files in development tree. #the macro my-dir provided build system, indicates path of current directory local_path:=$(call my-dir)  ##################################################################### #            build sqlite3                                            # ##################################################################### include $(clear_vars) local_c_includes := $(local_path)/sqlite-amalgamation-3070900 local_module:=sqlite3 local_src_files:=sqlite3.c #include $(build_static_library)  include $(build_shared_library) 

in cygwin move android-ndk-r8e folder , run this:

./ndk-build -c 'c:/eclipse/workspace/myapp' 

i able compile @ no rule make target error android ndk build sqlite. i'm stuck @ trying use library though right =/