jni>vi Android.mk:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_CFLAGS += -fPIE
LOCAL_LDFLAGS += -fPIE -pie
LOCAL_MODULE := test
LOCAL_SRC_FILES := test.c
#include $(BUILD_EXECUTABLE)
include $(BUILD_SHARED_LIBRARY)

jni>ndk-build NDK_DEBUG=1

Gdbserver      : [arm-linux-androideabi-4.6] libs/armeabi/gdbserver
Gdbsetup       : libs/armeabi/gdb.setup
Compile thumb  : test <= test.c
SharedLibrary  : libtest.so
Install        : libtest.so => libs/armeabi/libtest.so

libs/armeabi>adb forward tcp:12345 tcp:12345
libs/armeabi>arm-linux-androideabi-gdb
.........
.........
(gdb) target remote:12345
Remote debugging using :12345
0xb5f5d750 in ?? ()

(gdb) disass main
No symbol table is loaded.  Use the "file" command.

(gdb) file libtest.so
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from /test_dir/libs/armeabi/libtest.so...done.

WARNING: no debugging symbols found in /test_dir/libs/armeabi/libtest.so.
Either the binary was compiled without debugging information
or the debugging information was removed (e.g., with strip or strip -g).
Debugger capabilities will be very limited.
For further information: http://wiki/Main/GdbFaq#No_debugging_symbols_found

(gdb) disass main
No symbol table is loaded.  Use the "file" command.