clang -O2  -Wall -Wextra -Werror=implicit-function-declaration signal/sigtimedwait.c -o signal/sigtimedwait -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
../out/minix/basic/signal/sigtimedwait.o: In function `main':
signal/sigtimedwait.c:(.text+0x386): undefined reference to `__sigtimedwait50'
signal/sigtimedwait.c:(.text+0x3c1): undefined reference to `sigqueue'
signal/sigtimedwait.c:(.text+0x3d9): undefined reference to `__sigtimedwait50'
signal/sigtimedwait.c:(.text+0x45a): undefined reference to `__sigtimedwait50'
clang: error: linker command failed with exit code 1 (use -v to see invocation)