cc -O2 -pthread  -Wall -Wextra -Werror=implicit-function-declaration strings/ffsl.c -o strings/ffsl -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lintl -lcrypt
strings/ffsl.c: In function 'main':
strings/ffsl.c:11:15: error: implicit declaration of function 'ffsl' [-Werror=implicit-function-declaration]
   11 |  int output = ffsl(input);
      |               ^~~~
cc1: some warnings being treated as errors