clang -O2  -Wall -Wextra -Werror=implicit-function-declaration signal/pthread_sigmask.c -o signal/pthread_sigmask -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
../out/minix/basic/signal/pthread_sigmask.o: In function `main':
signal/pthread_sigmask.c:(.text+0x34b): undefined reference to `__libc_thr_sigsetmask'
signal/pthread_sigmask.c:(.text+0x3a5): undefined reference to `__libc_thr_sigsetmask'
clang: error: linker command failed with exit code 1 (use -v to see invocation)