1.add application link dependencies for all elf
2.add a global custom target to hold proptry in the toolchain file
3.add startup obj target
4.fix cpp lds error with kernel mod link elf lds
usage:
./build.sh qemu-armv7a:knsh --cmake
elf install in ${CMAKE_BINARY_DIR}/bin
Signed-off-by: xuxin19 <xuxin19@xiaomi.com>