you can double check here:
BTW, I can find the random.h with the toolchain:
owner@owner-ThinkPad-X220:~/LEAF/wp77/leaf-data/fx30catm/fx30-catm-legato$ find /opt/swi/WP77_R9.1/ -name “random.h”
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/debug/gcc-runtime/6.2.0-r0/gcc-6.2.0/build.arm-poky-linux-gnueabi.arm-poky-linux-gnueabi/arm-poky-linux-gnueabi/libstdc+±v3/include/bits/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/usr/include/config/hw/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/usr/include/uapi/linux/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/usr/include/trace/events/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/usr/include/linux/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/include/config/hw/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/include/uapi/linux/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/include/trace/events/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/src/kernel/include/linux/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/include/c++/6.2.0/tr1/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/include/c++/6.2.0/bits/random.h
/opt/swi/WP77_R9.1/sysroots/armv7a-neon-poky-linux-gnueabi/usr/include/linux/random.h