*** The GNU C library is currently not available for this platform.
*** So far nobody cared to port it and if there is no volunteer it
*** might never happen. So, if you have interest to see glibc on
*** this platform visit
*** http://www.gnu.org/software/libc/porting.html
*** and join the group of porters
byteswap.h 是glibc库的文件。
但是这个库不支持macOS，所以在macOS中只能换掉。
