Undefined Reference Error During Build and Test

[msaideroglu]

Skybox make build process gives an error at the end:
/tools_skybox/riscv32-gnu-toolchain/bin/../lib/gcc/riscv32-unknown-elf/12.2.0/../../../../riscv32-unknown-elf/bin/ld: /tools_skybox/riscv32-gnu-toolchain/bin/../lib/gcc/riscv32-unknown-elf/12.2.0/../../../../riscv32-unknown-elf/lib/libc.a(lib_a-exit.o): in function `.L2': exit.c:(.text.exit+0x30): undefined reference to `_exit'

then I give a try for quick demo with:
CONFIGS="-DEXT_GFX_ENABLE" ./ci/blackbox.sh --driver=simx --app=draw3d --args="-ttekkaman.cgltrace -w256 -h256" --cores=2

and getting this error:
/usr/bin/ld: /skybox/third_party/cocogfx/libcocogfx.a(png.o): in function `cocogfx::LoadPNG(char const*, std::vector<unsigned char, std::allocator<unsigned char> >&, unsigned int*, unsigned int*, unsigned int*)': png.cpp:(.text+0x37c): undefined reference to `png_check_sig'