cat @ mint-kitty : ~/projects/c/junk $ cat > rand_test.c
typedef unsigned char u_char;
#include <bsd/stdlib.h>
int main () { return (int) arc4random_uniform(100); }

cat @ mint-kitty : ~/projects/c/junk $ gcc -o rand_test ./rand_test.c -Wl,--verbose -lbsd | grep bsd
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libbsd.so failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libbsd.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libbsd.so succeeded
-lbsd (/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libbsd.so)

cat @ mint-kitty : ~/projects/c/junk $ ls -l /lib/x86_64-linux-gnu/libbsd*
lrwxrwxrwx 1 root root    15 Jan 28 00:11 /lib/x86_64-linux-gnu/libbsd.so.0 -> libbsd.so.0.8.2
-rw-r--r-- 1 root root 81040 Jan 28 00:11 /lib/x86_64-linux-gnu/libbsd.so.0.8.2