libnspr4-dev 2:4.16-1ubuntu2 (armhf binary) in ubuntu bionic

 This library provides platform independent non-GUI operating system
 facilities including:
  * threads,
  * thread synchronisation,
  * normal file I/O and network I/O,
  * interval timing and calendar time,
  * basic memory management (malloc and free),
  * shared library linking.
 .
 Install this package if you wish to develop your own programs using the
 NetScape Portable Runtime library.