third-party/mp4 没有完整源代码，只有.a和.so

[nanshanISCK]

third-party/mp4 没有完整源代码，只有.a和.so，使用gcc version 9.2.1 20191025 (GNU Toolchain for the A-profile
Architecture 9.2-2019.12 (arm-9.10))以外的编译器编译时会报错/usr/bin/ld: /mnt/SD_Card/SDK/third-party/mp4/lib/libmp4.a(3gp.o): relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `_ZNSt8ios_base4InitD1Ev@@GLIBCXX_3.4' which may bind externally can not be used when making a shared object; recompile with -fPIC