mac os 'math.h' file not found

In file included from thirdparty/harfbuzz/src/hb-aat-layout.cc:28:
In file included from thirdparty/harfbuzz/src/hb.hh:178:
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/math.h:300:15: fatal error: 'math.h' file not found

解决方式：

1. 将文件夹“/Library/Developer/CommandLineTools/usr/”重命名为usr-
2. 再将/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr拷贝到此目录下。