Error porting rlottie to arm platform

[wlq520501]

Hi, I'm trying to build a library for arm platform using rlottie, but I'm using arm-none-eabi-gcc.exe cross toolchain to compile it, and I get an error, error: 'mutex' in namespace 'std' does not name a type 124 | std::mutex mMutex; | ^ | ^~~~~ I'm not sure how to fix this, thanks a lot!