cc -O2 -pipe  -pthread  -Wall -Wextra -Werror=implicit-function-declaration stdlib/at_quick_exit.c -o stdlib/at_quick_exit -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread 
stdlib/at_quick_exit.c:14:7: error: call to undeclared function 'at_quick_exit'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
        if ( at_quick_exit(handler) )
             ^
stdlib/at_quick_exit.c:16:2: error: call to undeclared function 'quick_exit'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
        quick_exit(1);
        ^
2 errors generated.